Mesonephric and mesonephric-like carcinomas of the female genital tract: molecular characterization including cases with mixed histology and matched metastases

Napsin-A Expression in Mesonephric and Mesonephric-like Adenocarcinomas: Implications for Distinction From Clear Cell Carcinoma

Mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA) are rare gynecological neoplasms that sometimes exhibit morphologic overlap with clear cell carcinoma (CCC), which may lead to diagnostic challenges. Napsin-A is regarded as the most specific immunohistochemical marker of CCC, but its expression in MLA and MA has not been widely investigated. This study investigated the expression of Napsin-A in a series of MAs and MLAs to determine its utility in distinguishing these neoplasms from CCC. The cohort included 32 MLAs arising in the ovary, endometrium, abdominal wall, and sigmoid mesocolon, 13 cervical MLAs, 2 ovarian mesonephric-like carcinosarcomas, and 1 cervical mesonephric carcinosarcoma, with Napsin-A immunohistochemistry performed on whole-slide tissue sections. Napsin-A staining was positive in 17 of 48 cases (35.4%), with focal granular cytoplasmic expression ranging from 1% to 40%. In all, 13/32 (40.6%) MLAs, 2/13 (15.4%) MAs, and 2/3 (66.7%) mesonephric or mesonephric-like carcinosarcomas were positive. Our results demonstrate that Napsin-A is expressed in a significant subset of MLAs and MAs. Given the morphologic and immunohistochemical overlap, this may contribute to misclassification as CCC, especially in cases with ambiguous morphology. Pathologists should be aware of this diagnostic pitfall and employ a panel of markers rather than relying on a single marker.

Peritoneal washings analysis in endometrial cancer: Comparison of somatic mutation detection with panel sequencing and traditional cytology

OBJECTIVES

The prognostic significance of positive pelvic washings in endometrial cancer (EC) remains unknown, and little data exist regarding washings as a source of genetic information in relation to a patient's tumor. We sought to assess the feasibility of identifying EC mutations in peritoneal washings.

METHODS

Peritoneal washings from 21 biopsy-confirmed newly diagnosed patients with EC across disease stages between 09/2018 and 07/2019 were collected. Peritoneal washings, primary EC, and normal DNA samples were subjected to next-generation sequencing targeting 468 cancer-related genes. Sequencing results were compared to cytological analysis.

RESULTS

For the 21 EC cases included, cytology found 8 (38 %) of the peritoneal washings as positive, 7 (33 %) as negative, and 6 (29 %) as suspicious or rare-atypical cells. Based on molecular analysis, tumor mutations (TMs) were detected in 18/21 (86 %) of peritoneal washings. Overall, 11/21 (52 %) samples demonstrated concordant results between cytologic and molecular analysis, and all positive cytologic results were confirmed with molecular analysis. However, of cases with negative or suspicious cytology results, 77 % (10/13) were found to have TMs in washings. Five patients with negative cytology were positive on molecular analysis (5/7, 71 %), and 5 patients with suspicious washings demonstrated TMs (5/6, 83 %). Of the 10 EC patients who developed recurrences, regardless of stage, 5/10 (50 %) patients had positive cytology, whereas 9/10 (90 %) had TMs based on molecular analysis.

CONCLUSIONS

Mutational analysis of peritoneal washings using panel sequencing in EC is feasible. A substantial subset of patients with cytology-negative or suspicious washings had TMs detected.

Papillary and ductal patterns of mesonephric-like adenocarcinomas are often overlooked: a retrospective revaluation of over 1000 endometrial carcinomas

AIMS

Mesonephric-like adenocarcinoma (MLA) of the endometrium is often a diagnostic challenge, due to its morphological resemblance to other more common Müllerian neoplasms. This study aimed to retrospectively identify overlooked MLA in a large endometrial carcinoma cohort, using a combination of immunohistochemistry (IHC), morphology and KRAS sequencing.

METHODS AND RESULTS

IHC was conducted on 1094 endometrial carcinomas, identifying 16 potential MLA cases based on GATA3+ and/or TTF1+ and ER- staining patterns, which subsequently underwent detailed histological review, KRAS sequencing and ProMisE molecular classification. Of the IHC screen-positive cases, one was positive for both GATA3 and TTF1, nine were positive for GATA3 only and six were positive for TTF1 only. All IHC screen-positive cases were POLE wild-type. All five tumours in the NSMP category showed morphological features of MLA, while the three MMRd and eight p53abn tumours did not show MLA morphology. The five cases diagnosed as MLA on review were all originally diagnosed as low-grade endometrioid adenocarcinoma probably because of rare morphological patterns, being predominantly papillary or ductal. Four of the five cases harboured a KRAS mutation.

CONCLUSION

This study highlights the importance of a comprehensive diagnostic approach for accurately identifying endometrial MLA and for pathologists to be aware of papillary and ductal patterns in endometrial carcinoma assessment. Further exploration into the molecular landscape of MLA is essential for refining diagnostic criteria and developing targeted therapies.

Cellular origins of mucinous ovarian carcinoma

Mucinous ovarian carcinoma (MOC) is a rare histotype of epithelial ovarian cancer. Its origins are obscure: while many mucinous tumours in the ovary are metastases from the gastrointestinal tract, MOC can occur as an ovarian primary; however, the cell of origin is not well established. In this review we summarise the pathological, epidemiological, and molecular evidence for the cellular origins of MOC. We propose a model for the origins of the various tumours of the ovary with mucinous differentiation. We distinguish Müllerian from gastrointestinal-type mucinous differentiation. A small proportion of the latter arise from teratoma and a distinct terminology has been proposed. Other gastrointestinal mucinous tumours are associated with Brenner tumours and arise from their associated benign lesions, Walthard nests. The remaining mucinous tumours develop either through mucinous metaplasia in established Müllerian tumours or with even greater plasticity through gastrointestinal metaplasia of epithelial or mesothelial ovarian inclusions. This model remains to be validated and mechanistically understood and we discuss future research directions. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Clinicopathologic and Genomic Analysis of Uterine Serous Carcinomas Arising From Endometrial Hyperplasia

Uterine serous carcinoma (USC) typically arises from atrophic endometrium but may be associated with hyperplasia in 5% to 10% of cases. We sought to identify USC with concurrent hyperplasia and (i) define if these are clonally related, and (ii) determine if USC associated with hyperplasia is genetically distinct from USC without hyperplasia. Patients diagnosed with USC and hyperplasia from their hysterectomy specimen between January 1, 2014 and February 29, 2022 were identified. Hyperplasia and carcinoma were separately subjected to tumor-normal panel sequencing. Their repertoire of genetic alterations was compared with that of a separate cohort of atrophy-associated USCs. Of 267 USCs with clinical sequencing and slides available for review, 8 with concurrent carcinoma and hyperplasia had sufficient tissue for molecular studies. In 7 (87.5%) of these 8 cases, USC and hyperplasia were clonally related and shared multiple mutations, including TP53 in 4 cases (57%). In 1 case (USC4), USC and hyperplasia were unrelated at the genetic level, and the hyperplasia was TP53 wild-type. In another case (USC5), USC and TP53 wild-type hyperplasia shared 1 of 11 mutations while being distinct at the copy number level. The prevalence of ARID1A mutations was higher in hyperplasia-associated USC compared with atrophy-associated USC (43% vs. 0%, respectively; P=0.02). USC and co-occurring hyperplasia were clonally related in most cases, commonly harboring TP53 hotspot mutations in both components. These results suggest an alternative origin of tumorigenesis in this rare subset of endometrial cancers.

Mesonephric-like adenocarcinoma of the female genital tract: Pathologic diagnosis, clinical outcomes, and novel therapeutics

In 2016, McCluggage and colleagues first defined mesonephric-like adenocarcinoma (MLA) of the uterus and extra-uterine sites. Following this initial description, the World Health Organization officially recognized MLA as a type of uterine and ovarian carcinoma and subsequent studies have further refined the morphologic definition, immunohistochemical profile, molecular underpinnings, and clinical behavior in this rare entity. A consortium of pathologists, gynecologic oncologists, medical oncologists, radiation oncologists, as well as basic science collaborators with expertise in MLA was convened to develop consensus regarding the pathologic diagnosis, and to identify unanswered questions and priority areas for research. Here, we review the current understanding of MLA from a pathologic, molecular, and clinical standpoint.

Ovarian Mesonephric-Like Adenocarcinoma Arising from an Endometriotic Cyst with an Identical KRAS Mutation in Both Components: A Case Report

Mesonephric-like adenocarcinoma (MLA) is a rare tumor that occurs in the uterine corpus and ovary. It shares the morphological and immunohistochemical features of cervical mesonephric adenocarcinoma. Recent reports have suggested that a majority of ovarian MLAs are associated with endometriosis. Herein, we report the novel tumor of a 54-year-old Japanese woman with a history of bilateral ovarian endometriotic cysts who presented with abdominal distension. Pelvic magnetic resonance imaging revealed a 14-cm left ovarian cystic tumor with an intra-cystic solid mass. Histological examination revealed proliferation of columnar or cuboidal tumor cells forming round tubules, irregular tubular glands, fused glands, papillary structures, and solid nests.Additionally, associated endometriosis was observed in the cyst wall. The tumor cells were diffusely positive for GATA-binding protein 3 (GATA3) and negative for estrogen receptor. The tumor cells also showed wild-type p53, with retained expression of AT-rich interactive domain-containing protein 1A (ARID1) and phosphatase and tensin homolog (PTEN). Molecular analysis revealed an identical KRAS p.G12V mutation in the tumor and the endometriotic cyst. The present tumor elucidates the pathogenesis and molecular mechanisms of ovarian MLA and demonstrates that ovarian MLA is an endometriosis-associated neoplasm. Further investigation into the pathogenesis and molecular mechanisms of ovarian MLA may assist in identifying potential therapeutic targets for this rare condition.

Ovarian Mesonephric-Like Adenocarcinoma Arising Within a Serous Borderline Tumor: Insights into the Implications of Cell Origin-A Case Report and Review of the Literature

BackgroundMesonephric-like adenocarcinoma (MLA) is a rare and aggressive tumor found in the uterus and ovaries, characterized by unique morphological and immunophenotypic features similar to mesonephric carcinoma. It has been suggested that some tumors of MLA may originate from Müllerian-type lesions.Tumor PresentationA 54-year-old woman presented with abdominal discomfort and adnexal mass. Laboratory results revealed elevated carcinoembryonic antigen and CA-125 levels. Surgical findings showed ovarian MLA arising within a serous borderline tumor (SBT) with metastasis to lymph nodes, classified as FIGO stage IIIA2.Pathological FindingsThe SBT component exhibited typical papillary architecture, while the MLA component showed admixture of various architectural patterns, with intraluminal eosinophilic secretions. Immunohistochemistry revealed positivity for GATA3, TTF-1, and CD10, and negativity for ER and WT1. Molecular analysis identified a KRAS p.G12D mutation, typical of MLA, and a SMAD4 mutation.ConclusionThis tumor represents the ninth documented example of ovarian carcinoma with distinct components of MLA and low-grade serous neoplasm, SBT or low-grade serous carcinoma, providing valuable insights into the clinicopathological features and molecular characteristics of MLA, and contributing to the understanding of its origin and clinical behavior.

Ovarian mucinous tumors do not usually harbor a mesonephric-like component

BACKGROUND

The origin of primary mucinous ovarian tumors remains uncertain. Recently, a number of published cases suggested a possible mesonephric origin. The aim of this study is to investigate the association between these two types of proliferation and to determine whether the theory regarding this origin of ovarian mucinous tumors could be further supported.

MATERIAL AND METHODS

In our retrospective study, we included 406 patients diagnosed with a primary ovarian mucinous tumor. Clinical parameters were extracted from the patients' files. The slides were reexamined to identify any potential mesonephric-like elements. Foci harboring characteristics suggestive of a mesonephric-like component were subjected to an immunohistochemical analysis with GATA3 (Eurobio, L50-823) and TTF-1 (Dako-Agilent, clone 8G7G3/1) antibodies.

RESULTS

The mean age at diagnosis was 47.4 years (range 6-94 years). The tumors (n = 417, 15 bilateral cases) were mucinous cystadenomas/cystadenofibromas (n = 305), borderline mucinous tumors (n = 84) and mucinous carcinomas (n = 28). Associated Brenner tumors were present in 16 cases and teratomas in 8 cases. Morphological analysis revealed 64 cases with a component that could be considered mesonephric-like. Two of these were TTF-1 positive and one of them expressed GATA3 weakly and very focally. However, these were interpreted as non-specific of mesonephric differentiation.

CONCLUSION

Our series of 417 ovarian mucinous tumors revealed no associated mesonephric-like components. To date, only eight mucinous tumors associated with mesonephric-like foci have been reported in the literature. Our results indicate that the association between these two types of tissue is probably too rare to imply a potential role in their histogenesis.

Malignant Wolffian adnexal tumor in the ovary: a case report and literature review

Background

Wolffian adnexal tumor (WAT) is a rare neoplasm originating from the remnants of the Wolffian duct (mesonephric duct). Malignant WAT occurring in the ovary is exceptionally uncommon. This article presents a case of malignant WAT in the ovary, analyzing and discussing its histological features, diagnostic challenges, biological behavior, and treatment options in conjunction with relevant literature to enhance our understanding of this rare tumor.

Case presentation

A 64-year-old woman presented with an 8-month history of persistent abdominal pain and distension. An exploratory laparotomy revealed a small amount of pale-yellow ascites, a slightly atrophic uterus, and a left ovary without significant abnormalities. A solid mass measuring approximately 12 × 10 cm was observed between the left fallopian tube and ovary, displaying extensive dense adhesions to the posterior broad ligament and surrounding bowel. Frozen section pathology indicated a malignant tumor with necrotic areas suggestive of poorly differentiated carcinoma. The patient subsequently underwent a total hysterectomy, bilateral adnexectomy, omentectomy, pelvic lymphadenectomy, and pelvic adhesion release. Adjuvant chemotherapy with four cycles of paclitaxel and carboplatin (TC regimen) was administered, achieving normalization of tumor markers by the second cycle.

Conclusions

WAT is a rare entity within the spectrum of female reproductive system tumors, predominantly benign in nature. Due to its extremely low incidence, standardized treatment protocols remain elusive. Further research is warranted to establish effective management strategies and provide a reference for future cases.

Controversies in the Management of Mesonephric and Mesonephric-Like Adenocarcinomas of the Female Genital Tract

Mesonephric and mesonephric-like adenocarcinomas of the gynecologic tract are a rare subset of gynecologic tumors that are frequently associated with the presence of somatic KRAS mutations. Owing to their rare nature and ability to arise in different gynecologic sites, pathologic diagnosis is often challenging and under-represented. Immunohistochemistry and routine use of next-generation sequencing has allowed these cases to be more readily identified; however, there is still a paucity of clinical outcomes data, and the efficacy of treatment paradigms remains largely unknown. Historically, mesonephric and mesonephric-like adenocarcinomas were considered to be less responsive to systemic treatment, but response rates to first-line platinum-doublet chemotherapy for metastatic disease may be higher than initially suspected. Recurrent disease is often distant and located in the lungs, suggesting an important role of surveillance chest imaging. Given that most of these tumors are associated with somatic mitogen-activated protein kinase pathway mutations, a currently open phase II trial is assessing the dual RAF/MEK clamp avutometinib in combination with the FAK inhibitor defactinib in patients with recurrent mesonephric and mesonephric-like adenocarcinomas. Continued multi-institutional prospective trials are necessary to elucidate additional treatment options for these rare tumors.

Synchronous Bilateral Ovarian Carcinomas With Right Mesonephric-like Adenocarcinoma and Left High-grade Serous Carcinoma: A Case Report and Review of the Literature

Mesonephric-like adenocarcinomas (MLAs) are rare neoplasms of the uterus corpus and ovary, while high-grade serous carcinoma (HGSC) is the most common and lethal epithelial ovarian malignancy. We report a case of a 56-yr-old woman who presented with bilateral solid and cystic ovarian masses. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, lymphadenectomy, omentectomy, and peritoneal biopsies. Histopathologic examination of the bilateral ovarian masses revealed 1 ovary with MLA, and the other ovary showed HGSC in association with serous tubal intraepithelial carcinoma. The morphology, immunophenotypes, and molecular profiling of the HGSC and the MLA were distinct and as expected for the different tumor types: HGSC was diffusely positive for WT-1, estrogen receptor, and p53 (mutant pattern), while negative for GATA-3 and TTF-1; MLA was positive for GATA-3 and TTF-1, while negative for WT1, estrogen receptor, and p53 (wild-type pattern); both tumors were diffusely positive for PAX-8. The HGSC revealed a TP53 c.659A>G (p.Y220C) mutation, and the MLA revealed a KRAS c.34G>T (p. G12C) mutation and a PIK3CA c.1034A>T (p.N345I) mutation. To the best of our knowledge, this is the first reported case of synchronous bilateral ovarian carcinomas with MLA and contralateral ovarian HGSC.

Development of Antibody-Drug Conjugates for Malignancies of the Uterine Corpus: A Review

Despite recent advances in cancer treatment, the prognosis for uterine malignancies (carcinoma and sarcoma) requires further improvement. Antibody-drug conjugates (ADCs) have emerged as a novel class of anti-cancer therapeutic agents, and multiple ADCs have been approved for other types of cancer. In 2024, trastuzumab deruxtecan received approval from the US Food and Drug Administration for cancer types and became the first ADC approved for the treatment of uterine malignancies. Many ADCs are currently being investigated in uterine malignancies, and therefore, there is a need to gain a deeper understanding of ADCs. In this article, we aim to provide a comprehensive overview of the advancements in ADCs. The contents of this article include the structure and mechanism of action, an analysis of recent clinical trials, and expected future clinical questions. This article also focuses on uterine sarcoma, which is not often highlighted as a target for ADC treatment.

Mesonephric and Mesonephric-like Adenocarcinomas of the Gynecologic Tract: A Case Series and a Review of the Literature

We sought to present and describe all cases of mesonephric adenocarcinoma (MNAC) and mesonephric-like adenocarcinomas (MLAs) at our institution. These cancers are rare, morphologically similar tumors of the female reproductive tract. In this case series, we present 13 new cases of MNAC/MLA that were identified at St. Luke's University Health Network from 2016 to 2024. Demographics, clinical characteristics, and pathologic findings were collected from chart review. There were 6 uterine, 5 ovarian, and 2 cervical MNAC/MLAs. At presentation, more than half of the patients presented at early stages with 7, 2, 3, and 1 diagnosed at stages I, II, III, and IV, respectively. All patients underwent upfront surgical resection and were recommended adjuvant therapy. One patient declined adjuvant treatment. At the time of writing, 9 of 13 patients have completed treatment and have no evidence of disease, 1 is alive with disease, 1 is currently undergoing treatment, and 2 died of disease. Median overall survival (OS) was 15 mo (95% CI: 2.2-27.8 mo). Current literature regarding MNACs/MLAs suggests an overall poor prognosis, with the majority presenting at advanced stages. This case series describes patients diagnosed with early-stage disease and reports on their histopathology, treatment regimens, and clinical outcomes. The majority of these patients are without recurrence after upfront treatment. Continued surveillance of these patients to determine long-term outcomes is necessary to further elucidate overall prognosis.

Identifying mesonephric-like adenocarcinoma of the endometrium by combining SOX17 and PAX8 immunohistochemistry

AIMS

Mesonephric-like adenocarcinoma (MLA) of the endometrium or ovary is a rare but distinct endometrial carcinoma which has a combination of characteristic morphological, immunohistochemical (IHC) and molecular features. SOX17 has been recently identified as a highly sensitive and specific marker for endometrial and ovarian carcinomas. In this study, we aimed to investigate SOX17 expression in MLA together with other IHCs to differentiate MLAs from other endometrial carcinomas.

METHODS

Seventeen previously diagnosed endometrial/ovarian MLAs were collected, and multiple IHCs were performed. Additionally, we performed SOX17, PAX8 and ER on tissue microarrays (TMAs) composed of 652 endometrial carcinomas from 2012 to 2015 when MLA diagnostic criteria were not established.

RESULTS

All 17 MLAs showed diffuse strong positive PAX8, negative ER and variable TTF1/GATA3 staining. Notably, all MLAs showed negative (n = 10) or focal weak/moderate (n = 7) staining for SOX17, which is more diffuse and stronger than PAX8 in other endometrial carcinoma subtypes. This finding prompted us to screen TMAs with 652 endometrial carcinomas diagnosed before MLA by an approach of combined SOX17 and PAX8 IHCs, and 14 cases with positive PAX8 but negative/focal weak SOX17 were identified. We further studied the 14 cases by examining morphology and performing additional IHCs (TTF1, GATA3, ER and CD10) and would classify seven (50%) of them as MLAs based on morphological features and positive CD10, TTF1 and/or GATA3 staining.

CONCLUSION

Our results suggest that a combination of SOX17 and PAX8 IHCs would aid in diagnosing MLA if the results show strong positive PAX8, but negative SOX17.

STK11 Adnexal Tumor: Exploring the Association With Peutz-Jeghers Syndrome and its Distinction From Morphologic Mimickers

STK11 adnexal tumor is a novel malignant neoplasm of uncertain histogenesis frequently arising in a para-adnexal location and associated with Peutz-Jeghers syndrome in ∼50% of patients. Its broad morphologic spectrum and nonspecific immunohistochemical profile has resulted in misclassification in the past as a variety of other neoplasms including those of wolffian, sex cord-stromal, mesothelial, and epithelial derivation. This review focuses on the spectrum of adnexal neoplasms that may develop in Peutz-Jeghers syndrome, with particular emphasis on STK11 adnexal tumor and its differential diagnosis.

Evolutionary pathways in early-stage, non-myoinvasive endometrioid endometrial cancers of no specific molecular profile

OBJECTIVE

To characterize the genomic landscape of FIGO 2009 stage IA, non-myometrial invasive endometrioid endometrial cancers (ECs) of no specific molecular profile (NSMP) and define the earliest driver genetic alterations and subsequent tumor evolution.

METHODS

Early-stage (FIGO 2009 stage IA), non-myoinvasive endometrioid NSMP ECs subjected to clinical tumor-normal targeted sequencing between 2014 and 2022 were identified. ECs were dichotomized into low- and high-volume disease based on gross and histologic measurement using a cutoff of 1.8 cm3. Cancer cell fractions (CCF) of somatic mutations were determined.

RESULTS

A total of 171 noninvasive, FIGO 2009 stage I endometrioid ECs of NSMP subtype were identified, of which the majority (n = 139; 81 %) were FIGO grade 1. The median calculated volume of disease was 1.8 cm3 at diagnosis. The ECs had on average 6 pathogenic mutations, affecting known EC cancer-related genes, including PTEN (80 %), ARID1A (52 %), PIK3CA (52 %), CTNNB1 (39 %), PIK3R1 (37 %), and KRAS (29 %). Genomic alterations did not correlate with tumor volume. PTEN mutations had the highest CCFs. Unsupervised hierarchical clustering based on CCF revealed 4 main groups characterized by: 1. clonal alterations in PTEN accompanied by PIK3CA, PIK3R1, or ARID1A alterations, 2. mutations in PIK3CA co-occurring with ARID1A alterations, 3. KRAS mutations, particularly associated with 1q high-level gain, or 4. AKT1 mutations, which uniquely occurred without concurrent PTEN, PIK3CA, or PIK3R1 alterations.

CONCLUSION

Stage IA non-myoinvasive NSMP ECs show genomic heterogeneity suggestive of multiple evolutionary pathways. Further studies are warranted to define whether this is a sign of early genomic drift.

The Clinical Characteristics and Treatment Outcomes of Mesonephric Tumours of the Uterine Cervix: A Systematic Review and Proposal of Embryologically-Oriented Surgical Resection

Background/Objectives: Cervical mesonephric adenocarcinomas (MNACs) are among the rarest neoplasms of the female genital tract. Unlike the majority of cervical cancers, which are predominantly squamous in origin and strongly associated with HPV seropositivity, MNACs are distinct in both histology and pathophysiology. Despite their unique characteristics, MNACs have historically been managed in parallel with squamous cell carcinomas, resulting in a lack of optimised, evidence-based treatment protocols. In this systematic review, we aim to evaluate the current management strategies for MNACs and their associated clinical outcomes. Additionally, we critically appraise existing surgical and adjuvant therapies and propose embryologically oriented surgical techniques to achieve optimal tumour resection. Methods: We performed a systematic search across the MEDLINE, CENTRAL, EMBASE, and ClinicalTrials.gov databases from 1960 to June 2024. The search strategy employed a combination of keywords and MeSH terms, including "Uterine Cervical Neoplasms" [MeSH], "mesonephric tumour", "mesonephric neoplasm", and "mesonephric cancer". All relevant publications, including case reports and case series, were considered. Results: A total of 49 publications were finally included in the analysis, involving a thorough description of 91 MNAC cases. Most patients had stage I disease (70.8%) (n = 51). Hysterectomy was performed in 77 patients. The median follow-up was 29 months (range 1-199 months). Disease recurrence was observed in 35.2% (n = 25) of the cases, with the median disease-free survival (DFS) being 24 months (range 1-199). At the follow-up, 64.8% (n = 46) of patients remained in remission irrespective of the treatment modality, while 27.4% (n = 20) died due to disease progression. Conclusions: Mesonephric neoplasms of the uterine cervix are rare and clinically aggressive cancers that signify poor prognosis. Accurate identification and effective management can be challenging due to their particular anatomic and immunohistochemical characteristics. Therefore, a more tailored embryological-based approach should be considered for an optimal oncologic outcome.

Long-term breast cancer response to CDK4/6 inhibition defined by TP53-mediated geroconversion

Inhibition of CDK4/6 kinases has led to improved outcomes in breast cancer. Nevertheless, only a minority of patients experience long-term disease control. Using a large, clinically annotated cohort of patients with metastatic hormone receptor-positive (HR+) breast cancer, we identify TP53 loss (27.6%) and MDM2 amplification (6.4%) to be associated with lack of long-term disease control. Human breast cancer models reveal that p53 loss does not alter CDK4/6 activity or G1 blockade but instead promotes drug-insensitive p130 phosphorylation by CDK2. The persistence of phospho-p130 prevents DREAM complex assembly, enabling cell-cycle re-entry and tumor progression. Inhibitors of CDK2 can overcome p53 loss, leading to geroconversion and manifestation of senescence phenotypes. Complete inhibition of both CDK4/6 and CDK2 kinases appears to be necessary to facilitate long-term response across genomically diverse HR+ breast cancers.

STK11 (LKB1) immunohistochemistry is a sensitive and specific marker for STK11 adnexal tumours

AIMS

STK11 adnexal tumour is a rare, recently described malignant neoplasm that is associated with Peutz-Jeghers syndrome. [Correction added on 3 October 2024, after first online publication: 'ST11' in preceding sentence has been corrected to 'STK11' in this version.] It predominantly originates from the para-adnexal soft tissues and often shows secondary involvement of the fallopian tube and ovary. STK11 adnexal tumours have a broad differential diagnosis due to their variable morphology and non-specific immunoprofile, and diagnostic confirmation currently requires sequencing to identify an STK11 mutation. We investigate the diagnostic utility of STK11 (LKB1) immunohistochemistry (IHC) in a cohort of STK11 adnexal tumours and morphological mimics.

METHODS AND RESULTS

IHC for STK11 was performed on 122 tumours, including 17 STK11 adnexal tumours and 105 morphological mimics (10 female adnexal tumours of Wolffian origin, 22 adult granulosa cell tumours, 10 juvenile granulosa cell tumours, four Sertoli-Leydig cell tumours, two Leydig cell tumours, one Sertoli cell tumour, one steroid cell tumour, four extra-ovarian sex cord-stromal tumours, 16 ovarian endometrioid carcinomas, eight tubo-ovarian high-grade serous carcinomas, five ovarian mesonephric-like adenocarcinomas, 14 ovarian carcinosarcomas, five peritoneal malignant mesotheliomas, two pelvic plexiform leiomyomata and one ovarian solid pseudopapillary tumour). All STK11 adnexal tumours showed complete loss of cytoplasmic staining for STK11. All other tumour types showed retained cytoplasmic staining, except for one endometrioid carcinoma with mucinous differentiation which showed complete loss of STK11 expression and a high-grade serous carcinoma with subclonal loss.

CONCLUSIONS

STK11 is a highly sensitive and specific immunohistochemical marker for distinguishing STK11 adnexal tumour from its histological mimics, and can obviate the need for confirmatory molecular studies in the appropriate morphological context.

Mesonephric adenocarcinoma of the uterine cervix with a prominent spindle cell component

Mesonephric adenocarcinomas (MAs) with spindle cell components are rare malignant cervical tumours. In the present study, a retrospective analysis of these tumours was performed. Clinicopathological data were gathered from electronic surgical pathology records, and both immunohistochemistry and targeted next-generation sequencing (NGS) were performed. The present study included three postmenopausal female patients diagnosed with primary uterine cervical MA with prominent spindle cell components, aged 51-60 years. All patients underwent hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph node dissection. There were no recurrences or deaths after surgery. NGS analysis identified KRAS mutations in 2 cases and a PIK3-catalytic subunit α (PIK3CA) mutation in another. Spindle cell components may indicate MAs at an advanced stage. Spindle cell components in MAs are diagnostic pitfalls, and the use of immunohistochemical panels and molecular detection cases with overlapping morphological features is recommended. While KRAS mutations are the most common types of mutations in MAs with spindle cell components, the present study demonstrates that PIK3CA mutations can also occur independently in cases without KRAS mutations.

Histologic and Molecular Type Changes in Endometrial Cancer Recurrences in Comparison With Their Corresponding Primary Tumors

In this study, molecular alterations in endometrial carcinoma (EC) recurrences were analyzed. We aimed to identify genes implicated in tumor progression and to evaluate whether histologic and molecular type shifting occurs in recurrences. Thus, we analyzed 50 samples corresponding to 24 primary ECs (15 low-grade endometrioid endometrial carcinomas [LG-EECs] and 9 high-grade endometrial carcinomas) and their corresponding 26 recurrences. These were studied by immunohistochemistry, next-generation sequencing, and MLH1 promoter methylation. We observed shared mutations in all primary tumors and their recurrences, indicating a clonal relationship between both lesions. Most morphologic and molecular changes associated with progression were found in LG-EEC. In this group, 6 patients (40%) presented additional mutations in the recurrence. These mutations more frequently affected genes of the PI3K/AKT/PTEN pathway, implicating this pathway not only in tumor initiation but also in progression. In addition, 2 patients (13%) in which the primary tumor belonged to the nonspecific molecular profile subtype, shifted to the mismatch repair deficient (MMRd) subtype after the acquisition of MLH1 promoter methylation in the recurrence lesions. In 3 patients (20%) with MMRd, there was a change from LG-EEC to G3-EEC. One TP53-mutated LG-EEC transformed into an undifferentiated carcinoma in a mediastinal lymph node metastasis after losing the expression of SMARCA2 while preserving SMARCA4 and SMARCB1. Morphologic and molecular changes in EC recurrences, especially dedifferentiation and the acquisition of MMRd, should be considered for a correct diagnosis and treatment. MMRd should be tested in metastatic lesions, if available, in patients with primary tumors reported to be of a molecular subtype different from MMRd.

Endometrial Carcinosarcomas are Almost Exclusively of p53abn Molecular Subtype After Exclusion of Mimics

SUMMARY

Our aim was to assess the molecular subtype(s) and perform a detailed morphologic review of tumors diagnosed as carcinosarcoma in a population-based cohort. Forty-one carcinosarcomas were identified from a cohort of 973 endometrial carcinomas diagnosed in 2016. We assessed immunostaining and sequencing data and undertook expert pathology reviews of these cases as well as all subsequently diagnosed (post-2016) carcinosarcomas of no specific molecular profile (NSMP) molecular subtype (n=3) from our institutions. In the 2016 cohort, 37 of the 41 carcinosarcomas (91.2%) were p53abn, 2 (4.9%) were NSMP, and 1 each (2.4%) were POLE mut and mismatch repair deficiency molecular subtypes, respectively. Of the 4 non-p53abn tumors on review, both NSMP tumors were corded and hyalinized (CHEC) pattern endometrioid carcinoma, the mismatch repair deficiency tumor was a grade 1 endometrioid carcinoma with reactive stromal proliferation, and the POLE mut tumor was grade 3 endometrioid carcinoma with spindle cell growth, that is, none were confirmed to be carcinosarcoma on review. We found 11 additional cases among the 37 p53abn tumors that were not confirmed to be carcinosarcoma on the review (3 undifferentiated or dedifferentiated carcinomas, 5 carcinomas with CHEC features, 2 carcinomas showing prominent reactive spindle cell stroma, and 1 adenosarcoma). In the review of institutional cases reported as NSMP carcinosarcoma after 2016, 3 were identified (1 adenosarcoma and 2 mesonephric-like adenocarcinoma on review). In this series, all confirmed endometrial carcinosarcomas were p53abn. The finding of any other molecular subtype in a carcinosarcoma warrants pathology review to exclude mimics.

Mixed Mesonephric-like Adenocarcinoma, Clear Cell Carcinoma, and Endometrioid Carcinoma Arising from an Endometriotic Cyst

Mesonephric-like adenocarcinoma is a rare neoplasm of the uterine corpus and ovary. Unlike prototypical mesonephric adenocarcinoma of the uterine cervix, which is considered of Wolffian origin, recent evidence suggests that mesonephric-like adenocarcinoma is a Mullerian tumor associated with endometriosis. We report here on a 48-year-old woman with a mixed carcinoma of the ovary that consisted of mesonephric-like adenocarcinoma, clear cell carcinoma, and endometrioid carcinoma, arising from an endometriotic cyst. The mesonephric-like adenocarcinoma consisted of cuboidal cells with vesicular nuclei presenting with a tubular, ductal, papillary, and solid architecture forming nodules. Each component showed distinct immunophenotypes that were consistent with their morphology. The mesonephric-like adenocarcinoma showed diffuse positive staining for paired box 8 and GATA binding protein 3, and negative staining for estrogen and progesterone receptors. A p53 stain exhibited wild-type immunoreactivity. A complete loss of AT-rich interactive domain-containing protein 1A (ARID1A) expression was suggestive of an ARID1A mutation. Manual macrodissection and Sanger sequencing revealed identical KRAS and PIK3CA mutations in all three components. To the best of our knowledge, this is the first report of mesonephric-like adenocarcinoma combined with a clear cell carcinoma and endometrioid carcinoma, which supports the hypothesis that mesonephric-like adenocarcinoma is an endometriosis-associated neoplasm. The report also highlights a potential pitfall in diagnosing mesonephric-like adenocarcinoma combined with clear cell carcinoma.

Ovarian Mesonephric-like Adenocarcinoma: Its Prevalence in a Japanese High-Volume Cancer Center and a Literature Review on Therapeutic Targets

BACKGROUND

Ovarian mesonephric-like adenocarcinoma (MLA) is a newly described histological type known for its aggressive behavior. This study aims to determine the frequency of ovarian MLA, review the existing literature, and elucidate its clinicopathological characteristics, including the potential therapeutic targets.

METHODS

We retrospectively reviewed the pathological diagnoses of 501 primary ovarian cancer surgical cases at our institution from 2010 to 2023. MLAs exhibiting typical morphological and immunohistochemical features were included. The frequency and clinicopathological characteristics of these cases were summarized. Additionally, we conducted a literature search using PubMed to collect and summarize previously reported cases of ovarian MLAs.

RESULTS

Among the 501 primary ovarian cancer cases, we identified 3 cases (0.6%) of MLA. The patients were 52-76 years old, and the initial FIGO stages were IC1 (two cases) and IIIB (one case). All the cases exhibited HRP, pMMR, PD-L1 negativity (CPS < 1), and low HER2 expression. Two cases experienced metastatic recurrence. A literature review identified 97 cases of MLA. The MLAs frequently exhibited KRAS mutations (90%, 38/42), with a recurrence rate of 39% (26/67).

CONCLUSION

MLAs accounted for 0.6% of malignant ovarian tumors at our institution, all of which were advanced or recurrent cases. These cases showed HRP, pMMR, and PD-L1 negativity, indicating a lack of current therapeutic targets. The literature also reported a high incidence of advanced and recurrent cases, highlighting the need for accurate diagnosis and the development of new treatments. The frequent KRAS mutations suggest a potential therapeutic target for recurrent or metastatic MLA.

Mesonephric-type adenocarcinomas of the ovary: prevalence, diagnostic reproducibility, outcome, and value of PAX2

Mesonephric-type (or -like) adenocarcinomas (MAs) of the ovary are an uncommon and aggressive histotype. They appear to arise through transdifferentiation from Müllerian lesions creating diagnostic challenges. Thus, we aimed to develop a histologic and immunohistochemical (IHC) approach to optimize the identification of MA over its histologic mimics, such as ovarian endometrioid carcinoma (EC). First, we screened 1,537 ovarian epithelial neoplasms with a four-marker IHC panel of GATA3, TTF1, ER, and PR followed by a morphological review of EC to identify MA in retrospective cohorts. Interobserver reproducibility for the distinction of MA versus EC was assessed in 66 cases initially without and subsequently with IHC information (four-marker panel). Expression of PAX2, CD10, and calretinin was evaluated separately, and survival analyses were performed. We identified 23 MAs from which 22 were among 385 cases initially reported as EC (5.7%) and 1 as clear cell carcinoma. The interobserver reproducibility increased from fair to substantial (κ = 0.376-0.727) with the integration of the four-marker IHC panel. PAX2 was the single most sensitive and specific marker to distinguish MA from EC and could be used as a first-line marker together with ER/PR and GATA3/TTF1. Patients with MA had significantly increased risk of earlier death from disease (hazard ratio = 3.08; 95% CI, 1.62-5.85; p < 0.0001) compared with patients with EC, when adjusted for age, stage, and p53 status. A diagnosis of MA has prognostic implications for stage I disease, and due to the subtlety of morphological features in some tumors, a low threshold for ancillary testing is recommended.

Synchronous Bilateral Ovarian Mesonephric-like Adenocarcinomas with Separate Origins from High-Grade Mullerian Adenosarcoma and Endometriosis: Report of a Rare Case

Mesonephric-like adenocarcinoma (MLA) of the ovary is a recently recognized, rare malignancy with aggressive clinical behavior, and is thought to originate from Mullerian epithelium with mesonephric transdifferentiation. Emerging evidence suggests that MLA may be classified as an endometriosis-associated neoplasm. The presence of a sarcomatous component within MLA is extremely rare, with common differential diagnoses including the spindle cell component of MLA, carcinosarcoma, as well as mixed Mullerian adenocarcinoma and adenosarcoma. Herein, we report a 58-year-old Chinese woman with bilateral ovarian solid-cystic masses. The left ovarian mass comprised a biphasic tumor with a predominantly high-grade sarcomatous component displaying heterologous mesenchymal differentiation, including liposarcoma, rhabdomyosarcoma and chondrosarcoma-like areas, with a null-type p53 expression. The epithelial component ranged from a bland appearance in areas diagnostic of adenosarcoma to a clearly invasive carcinoma, both with mesonephric-like phenotype, being negative for estrogen receptor, progesterone receptor, and Wilms' tumor 1, variably positive for paired box gene 8, GATA binding protein 3, and thyroid transcription factor 1, with a wild-type p53 expression. The differing p53 expression between the epithelial and sarcomatous elements mitigated against a diagnosis of carcinosarcoma. The right ovarian mass showed endometriosis with focal direct evidence of the development of malignancy within a benign endometriotic cyst, exhibiting the identical immunoprofile of MLA but originating as another malignancy. To the best of our knowledge, this case represents the first reported case of synchronous bilateral ovarian MLAs with separate origins, from high-grade Mullerian adenosarcoma and endometriosis respectively, which broadens the morphologic spectrum of MLA and provides further evidence supporting the Mullerian origin theory.

Premature Classification of Early-stage Endometrioid Ovarian Carcinoma With Mesonephric-like Differentiation as Mesonephric-like Adenocarcinoma

Ovarian mesonephric-like adenocarcinoma (MLA) is a rare tumor with potential origins in endometriosis and Müllerian-type epithelial tumors. The morphologic patterns of MLA overlap with those of endometrioid ovarian carcinoma (EnOC). We speculated that a subset of MLAs would be classified as EnOCs. In this study, we attempted to identify MLAs from malignant endometrioid tumors. Given that the study patients with MLAs had both endometrioid-like and mesonephric-like morphologies, we defined mesonephric-like differentiation (MLD) as an endometrioid tumor with focal or diffuse MLA morphology and immunophenotype. Twelve patients exhibited mesonephric-like morphologic patterns. Immunohistochemistry analysis for CD10, TTF-1, estrogen receptor (ER), GATA3, calretinin, and PAX8 expression was done using whole-section slides. Two patients without the MLA immunophenotype were excluded. Ten patients with EnOCs with MLD (8.3%) were identified from a cohort of 121 patients with malignant endometrioid tumors. All 10 patients were positive for TTF-1 and/or GATA3. Most patients were ER-negative. Morphologically, MLD was associated with papillary thyroid carcinoma-like nuclei, flattened cells, tubular, nested, reticular, or glomeruloid architecture, and infiltrative growth. All 10 patients had pre-existing endometriosis and/or adenofibromas. Among the EnOCs with MLD, 5 had coexisting components such as EnOC grade 1 [(G1), cases 4, 7, and 9], mucinous borderline tumor (case 1), and dedifferentiated carcinoma (case 10), with distinct borders between EnOC with MLD and the other components. Nine of the 10 MLA patients (90%) harbored KRAS hotspot mutations. In addition, 4 patients harboring other components shared common KRAS hotspot mutations. No significant prognostic differences were observed between patients with and without MLD. Based on our findings, we suggest that EnOC with MLD, especially in the early stages and without high-grade components, should be considered a subtype of EnOC. Overtreatment should be avoided in such patients, particularly in the early stages. In this study, as the characteristics between EnOC with MLD and MLA were not distinguishable, we considered both conditions to be on the same spectrum. EnOCs with MLD exhibit the MLA phenotype during disease progression and are prematurely classified as MLA. Nevertheless, more patients with EnOC who have MLD/MLA are required for a more robust comparison between conventional EnOC according to staging and grading.

Mucinous cystadenoma and benign mesonephric-like proliferation in the ovary - Further evidence for clonal relationship

Mesonephric-like adenocarcinomas rarely occur in the uterus and the ovary. Benign mesonephric-like (ML) proliferations and hyperplasia have been described solely within the ovary. Pathogenetic data are very limited. We report a case with microscopic focus of benign ML-proliferation in association with mucinous cystadenoma in the ovary. The immunophenotype was distinct (mucinous tumor: focal weak nuclear positivity for PAX-8, CK 7, patchy cytoplasmic positivity for p16 and negativity for estrogen receptor, CD 10, TTF-1, p53 wildtype; mesonephric component: diffusely positive for PAX-8, CK 7, luminal CD 10, TTF-1, focal staining for estrogen receptor, patchy cytoplasmic for p16, p53 wildtype). On NGS-analysis there was clonal mutation of KRAS p.G12C. The data provide additional evidence for the concept of transdifferentiation (Müllerian tissue representing Wolffian/mesonephric features on histology and immunostaining) within the pathogenesis of mesonephric proliferation of the female genital tract and demonstrate the clonal relationship between these distinct morphologic components.

Adenoid cystic carcinoma of the Bartholin's gland is underpinned by MYB- and MYBL1- rearrangements

OBJECTIVE

Adenoid cystic carcinoma (AdCC) of the Bartholin's gland (AdCC-BG) is a very rare gynecologic vulvar malignancy. AdCC-BGs are slow-growing but locally aggressive and are associated with high recurrence rates. Here we sought to characterize the molecular underpinning of AdCC-BGs.

METHODS

AdCC-BGs (n = 6) were subjected to a combination of RNA-sequencing, targeted DNA-sequencing, reverse-transcription PCR, fluorescence in situ hybridization (FISH) and MYB immunohistochemistry (IHC). Clinicopathologic variables, somatic mutations, copy number alterations and chimeric transcripts were assessed.

RESULTS

All six AdCC-BGs were biphasic, composed of ductal and myoepithelial cells. Akin to salivary gland and breast AdCCs, three AdCC-BGs had the MYB::NFIB fusion gene with varying breakpoints, all of which were associated with MYB overexpression by IHC. Two AdCC-BGs were underpinned by MYBL1 fusion genes with different gene partners, including MYBL1::RAD51B and MYBL1::EWSR1 gene fusions, and showed MYB protein expression. Although the final AdCC-BG studied had MYB protein overexpression, no gene fusion was identified. AdCC-BGs harbored few additional somatic genetic alterations, and only few mutations in cancer-related genes were identified, including GNAQ, GNAS, KDM6A, AKT1 and BCL2, none of which were recurrent. Two AdCC-BGs, both with a MYB::NFIB fusion gene, developed metastatic disease.

CONCLUSIONS

AdCC-BGs constitute a convergent phenotype, whereby activation of MYB or MYBL1 can be driven by the MYB::NFIB fusion gene or MYBL1 rearrangements. Our observations further support the notion that AdCCs, irrespective of organ site, constitute a genotypic-phenotypic correlation. Assessment of MYB or MYBL1 rearrangements may be used as an ancillary marker for the diagnosis of AdCC-BGs.

Ovarian Mesonephric-Like Adenocarcinoma With Recurrent Liver Metastases: A Case Report with Analysis of Therapeutic Molecular Targets

Ovarian mesonephric-like adenocarcinoma (MLA) is a rare cancer subtype. We describe a patient with ovarian MLA wherein liver metastases developed 1 month after surgery. A phenotypic analysis of the tumor was performed to identify molecular therapeutic targets. A 53-year-old woman, without any symptoms, underwent uterine cancer screening. Transvaginal ultrasonography revealed an ovarian mass, and subsequent pelvic magnetic resonance imaging showed a 13 × 10 cm multicystic ovarian lesion with a solid part. No extra ovarian lesions were observed and a staging laparotomy was performed. Pathological examination revealed an MLA of the left ovary (stage IC1). The tumor comprised tumor cells in a tubular pattern with intraluminal eosinophilic material, as well as mixed glandular and papillary, cord-like, and solid patterns. Endometriosis was also observed. Immunohistochemically, the tumor cells were positive for PAX8, GATA3 (focal), TTF1 (focal), and CD10 (luminal) and negative for the estrogen receptor, progesterone receptor, and WT1. One month after surgery, computed tomography revealed multiple liver metastases. Additional immunohistochemistry for therapeutic targets revealed that the tumor cells were weakly positive for human epidermal growth factor receptor 2 (focal; score 1+), pan-tropomyosin receptor kinase-negative, programmed death-ligand 1-negative, and PMS2 and MSH6 intact. The companion homologous recombination deficiency test (MyChoice®) showed homologous recombination repair proficiency. These findings suggest that poly(ADP-ribose) polymerase inhibitors and immune checkpoint inhibitors may not be effective treatment options. A literature review revealed that data on therapeutic targets in MLA are scarce. In summary, we report a patient with ovarian MLA showing an aggressive clinical course and the phenotypic analysis of the tumor may contribute to the identification of therapeutic targets for MLA.

Special Considerations in Classification and Workup of Endometrial Carcinomas

CONTEXT.—

A variety of uncommon malignant endometrial tumors can be challenging to diagnose because of overlapping morphology with more common entities. In some cases, immunohistochemical stains and/or molecular testing allow for more definitive diagnosis or prognostication.

OBJECTIVE.—

To review classic morphologic features of uncommon endometrial tumors, pathologic features of these tumors and their mimics, and the evidence for use of immunohistochemistry and molecular testing in the diagnosis of these tumors.

DATA SOURCES.—

University of Michigan (Ann Arbor) cases and review of pertinent literature about each entity.

CONCLUSIONS.—

Although each of these uncommon endometrial tumors has morphologic mimics, key histologic features, immunohistochemical stains, and molecular testing allow for accurate classification.

Mesonephric and mesonephric-like adenocarcinomas of gynecologic origin: A single-center experience with molecular characterization, treatment, and oncologic outcomes

OBJECTIVES

Mesonephric (MA) and mesonephric-like (MLA) adenocarcinomas are rare cancers, and data on clinical behavior and response to therapy are limited. We sought to report molecular features, treatment, and outcomes of MA/MLA from a single institution.

METHODS

Patients with MA (cervix) or MLA (uterus, ovary, other) treated at Memorial Sloan Kettering Cancer Center (MSK) from 1/2008-12/2021 underwent pathologic re-review. For patients with initial treatment at MSK, progression-free survival (PFS1) was calculated as time from initial surgery to progression or death; second PFS (PFS2) was calculated as time from start of treatment for recurrence to subsequent progression or death. Overall survival (OS) was calculated for all patients. Images were retrospectively reviewed to determine treatment response. Somatic genetic alterations were assessed by clinical tumor-normal sequencing (MSK-Integrated Mutation Profiling of Actionable Cancer Targets [MSK-IMPACT]).

RESULTS

Of 81 patients with confirmed gynecologic MA/MLA, 36 received initial treatment at MSK. Sites of origin included cervix (n = 9, 11%), uterus (n = 42, 52%), ovary (n = 28, 35%), and other (n = 2, 2%). Of the 36 patients who received initial treatment at MSK, 20 (56%) recurred; median PFS1 was 33 months (95% CI: 17-not evaluable), median PFS2 was 8.3 months (95% CI: 6.9-14), and median OS was 87 months (95% CI: 58.2-not evaluable). Twenty-six of the 36 patients underwent MSK-IMPACT testing, and 25 (96%) harbored MAPK pathway alterations.

CONCLUSION

Most patients diagnosed with early-stage disease ultimately recurred. Somatic MAPK signaling pathway mutations appear to be highly prevalent in MA/MLA, and therapeutics that target this pathway are worthy of further study.

Molecular features for timely cancer diagnosis and treatment - tumors of the ovary, fallopian tube and endometrium

Gynecologic pathology has moved, within only a few years, from being a diagnostic area devoid of molecular testing into a diagnostic discipline in which such analyses are becoming routine. The direct relevance of molecular characterization to the choice of treatment of patients with carcinomas originating in both the uterus and adnexae makes it likely that such testing will only expand along with our understanding of the molecular make-up of these tumors. As a consequence, gynecologic pathologists have become an integral part of patient management, rather than lab personnel providing external services.In parallel, molecular testing is expanding as a tool for diagnosing rare tumors affecting these organs, including soft tissue tumors, sex cord-stromal tumors and germ cell tumors, as well as other rare entities. Increased knowledge in this area bears directly on the ability to diagnose these tumors in a reproducible manner, as well as recognize and consult on genetic diseases. Hopefully, despite the inherent difficulty in studying rare cancers, it will also translate into new therapeutic options for the malignant ones among these rare cancers.

A Case of Uterine Tumor Resembling Ovarian Sex Cord Tumor With Prominent Myxoid Features

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare tumor with low malignant potential that commonly occurs in middle age. Although more than 100 cases have been reported to date, myxoid morphology is not well documented. Here, we present a 75-yr-old woman with abnormal vaginal bleeding, with an 8-cm mass in the uterine corpus detected by irregular, high-intensity signaling on T2-weighted imaging. The uterine mass had a glistening mucinous appearance on gross examination. Microscopically, most of the tumor cells were floating in the myxoid stroma. The tumor cells formed clusters or nests with abundant cytoplasm, while some exhibited trabecular or rhabdoid appearances. Immunohistochemically, tumor cells were positive for pancytokeratin (AE1/AE3), α-smooth muscle actin, CD10, progesterone receptor, and some sex cord markers such as calretinin, inhibin, CD56, steroidogenic factor-1. Electron microscopy demonstrated epithelial and sex cord differentiation. This tumor was negative for JAZF1-JJAZ1 fusion gene that is frequently found in low-grade endometrial stromal sarcoma. Fusion genes related to UTROSCT, including NCOA2/3 , were not detected by reverse transcription polymerase chain reaction. The present case suggests that UTROSCT should be included in the differential diagnosis of myxoid uterine tumors.

Mesonephric-like adenocarcinoma of the ovary with squamoid morular metaplasia, aberrant β-catenin expression, and concurrent FGFR2 and CTNNB1 mutations: a case report

In general, endometrioid-defining features such as squamoid morular metaplasia are not thought to be associated with mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA). Here, we report a case of FGFR2-mutated ovarian MLA with squamoid morular metaplasia accompanied by aberrant nuclear and cytoplasmic β-catenin expression and CTNNB1 mutation. Histologically, the tumor showed classical MLA histology, including well-formed glands with intraluminal eosinophilic secretions and cells with papillary thyroid carcinoma-like nuclei. Squamoid morular metaplasia was intimately associated with the tumor. Glandular epithelial elements, including those immediately associated with the squamoid morules, were negative for ER, but positive for both GATA3 and PAX8; aberrant β-catenin expression was limited to the squamoid morules. This case illustrates the ability of mesonephric neoplasia to exhibit histological features previously thought to be restricted to an endometrioid phenotype.

Mesonephric-like adenocarcinoma harbours characteristic copy number variations and a distinct DNA methylation signature closely related to mesonephric adenocarcinoma of the cervix

Mesonephric-like adenocarcinoma (MLA) of the female genital tract is an uncommon histotype that can arise in both the endometrium and the ovary. The exact cell of origin and histogenesis currently remain unknown. Here, we investigated whole genome DNA methylation patterns and copy number variations (CNVs) in a series of MLAs in the context of a large cohort of various gynaecological carcinoma types. CNV analysis of 19 MLAs uncovered gains of chromosomes 1q (18/19, 95%), 10 (15/19, 79%), 12 (14/19, 74%), and 2 (10/19, 53%), as well as loss of chromosome 1p (7/19, 37%). Gains of chromosomes 1q, 10, and 12 were also identified in the majority of mesonephric adenocarcinomas of the uterine cervix (MAs) as well as subsets of endometrioid carcinomas (ECs) and low-grade serous carcinomas of the ovary (LGSCs) but only in a minority of serous carcinomas of the uterine corpus (USCs), clear cell carcinomas (CCCs), and tubo-ovarian high-grade serous carcinomas (HGSCs). While losses of chromosome 1p together with gains of chromosome 1q were also identified in both MA and LGSC, gains of chromosome 2 were almost exclusively identified in MLA and MA. Unsupervised hierarchical clustering and t-SNE analysis of DNA methylation data (Illumina EPIC array) identified a co-clustering for MLAs and MAs, which was distinct from clusters of ECs, USCs, CCCs, LGSCs, and HGSCs. Group-wise comparisons confirmed a close epigenetic relationship between MLA and MA. These findings, in conjunction with the established histological and immunophenotypical overlap, suggest bona fide mesonephric differentiation, and support a more precise terminology of mesonephric-type adenocarcinoma instead of MLA in these tumours. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Case Report: The first report of PPP2R1A mutations in mesonephric-like adenocarcinoma of endometrial carcinoma

We performed clinical treatment, histopathology, immunohistochemistry and molecular analyses. To compare with the published literature and have a reference overview. A 57-year-old woman and a 77-year-old woman presented with mesonephric-like adenocarcinoma of endometrium at an early clinical stage. The former had no deep myometrial infiltration and no regional lymph node involvement. The latter had deep myometrial infiltration, presence of LVSI and no regional lymph node involvement. Both of the tumor cells were positive for PAX8, GATA-3,CD-10,TTF-1,AE1/AEs,Ki67,P53 and P16 in immunohistochemical staining (IHC)Test. Primary tumors were examined for gene mutations by next generation sequencing. The former was identified KRAS mutation. The latter had KRAS,PIKCA and PPP2R1A mutations. To our knowledge, it is the first time that PPP2R1A(protein phosphatase 2,regulatory subunit A,α) mutation in MLA is reported in English literature.

Ovarian RASoma With Mesonephric-like Adenocarcinoma and Mixed Mullerian Components: A Case Report With Molecular Analysis Demonstrating Multidirectional Mullerian Differentiation

Gynecologic carcinomas with RAS mutations may show a wide spectrum of histologic types, including mixed types. We present the case of a 63-yr-old patient diagnosed with an ovarian tumor harboring a mesonephric-like adenocarcinoma in a background of mixed mesonephric-like, mucinous, and endometrioid components. Molecular analysis revealed that all 3 components shared the same clonal KRAS mutation (p.G12A) and chromosome 1q gain. Based on shifts in clonality, copy number gains, and acquisition of an additional mutation, our data suggest that the mucinous component likely constituted the substrate from which the mesonephric-like and endometrioid components arose.

Mesonephric-like adenocarcinoma of the female genital tract: possible role of KRAS-targeted treatment-detailed molecular analysis of a case series and review of the literature for targetable somatic KRAS-mutations

PURPOSE

Mesonephric-like adenocarcinomas (MLA) of the female genital tract represent a rare and relatively recently described neoplasm exhibiting characteristic morphologic and immunohistochemical findings commonly associated with a KRAS-mutation. Most cases display an aggressive clinical behavior, but knowledge about treatment approaches is limited, especially for targeting KRAS.

METHODS

We report a series of eight cases with a detailed molecular analysis for KRAS. These cases as well as the data of previously published cases with detailed information regarding KRAS-mutational events were reviewed for a potential targeted approach and its prognostic impact.

RESULTS

Both the uterine and ovarian MLA harbor a somatic KRAS-mutation in about 85% of the reported cases, affecting the hotspot codons 12 and 13. 15.7% of the endometrial and 15.6% of ovarian MLA are wild type for KRAS. A p.G12A-alteration was seen in 5.6% (5/89) of the endometrial and in 6.2% (2/32) of the ovarian tumors, for p.G12C in 7.9% and 6.2%, for p.G12D in 32.6% and 34.5% and for p.G12V in 36% and 37.5%, respectively. Very limited data are available regarding the prognostic impact of different mutational sites within the KRAS-gene without significant prognostic impact.

CONCLUSION

Because of a specific p.G12C-KRAS somatic mutation, only the minority of MLA (7.9% with uterine and 6.2% with ovarian primary) are potentially targetable by sotarasib in that rare but aggressive subtype of adenocarcinoma of the female genital tract. Until now, the different location of a somatic KRAS-mutation is of no prognostic impact.

Mesonephric Adenomyofibroma: A Biphasic Vaginal Mass of Mesonephric Type With Molecular Analysis: A Case Report of a Rare Entity

Mesonephric neoplasms of the lower female genital tract are rare. To date, there are scarce reports of benign biphasic vaginal mesonephric lesions, and none have included immunohistochemical and/or molecular analysis. A biphasic neoplasm of mesonephric-type was incidentally identified in the vaginal submucosal tissue of a 55-yr-old woman who underwent a right salpingo-oophorectomy for an ovarian cyst. The well-circumscribed, 5 mm nodule exhibited white-tan, firm homogenous cut surfaces. Microscopic examination showed a lobular arrangement of glands with columnar to the cuboidal epithelium and intraluminal eosinophilic secretions, embedded within a myofibromatous stroma. Cytologic atypia and mitotic activity were absent. Immunohistochemical staining for PAX8 and GATA3 demonstrated diffuse expression in the glandular epithelium, CD10 exhibited a patchy luminal expression pattern, while TTF1, ER, PR, p16, and NKX3.1 were negative. Desmin highlighted a subset of the stromal cells, but myogenin was negative. Whole exome sequencing demonstrated variants of unknown significance in multiple genes including PIK3R1 and NFIA . The morphologic and immunohistochemical profiles are consistent with a benign mesonephric neoplasm. This is the first report describing the immunohistochemical and whole exome sequencing results for a benign biphasic vaginal mesonephric neoplasm. To the best of our knowledge, benign mesonephric adenomyofibroma has not been previously reported in this anatomic location.

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Genomic and Immunohistochemical Profiling with Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution

Data on genetic and immunophenotypical characteristics of uterine mesonephric-like adenocarcinoma (MLA) remain limited. Therefore, we aimed to investigate the clinicopathological, immunohistochemical, and molecular features of uterine MLA. We performed targeted sequencing, array comparative genomic hybridization, and immunostaining in 17, 13, and 17 uterine MLA cases, respectively. Nine patients developed lung metastases. Eleven patients experienced disease recurrences. The most frequently mutated gene was Kirsten rat sarcoma viral oncogene homolog (KRAS; 13/17). Both the primary and matched metastatic tumors harbored identical KRAS (3/4) and phosphatase and tensin homolog deleted on chromosome 10 (1/4) mutations, and did not harbor any additional mutations. A total of 2 of the 17 cases harbored tumor protein 53 (TP53) frameshift insertion and deletion, respectively. Chromosomal gains were detected in 1q (13/13), 10 (13/13), 20 (10/13), 2 (9/13), and 12 (6/13). Programmed cell death-ligand 1 overexpression or mismatch repair deficiency was not observed in any of the cases. Initial serosal extension and lung metastasis independently predicted recurrence-free survival with hazard ratios of 6.30 and 7.31, respectively. Our observations consolidated the clinicopathological and molecular characteristics of uterine MLA. Both clinicians and pathologists should consider these features to make an accurate diagnosis of uterine MLA and to ensure appropriate therapeutic management of this rare entity.

Clinicopathologic and genomic features of lobular like invasive mammary carcinoma: is it a distinct entity?

This study describes "lobular-like invasive mammary carcinomas" (LLIMCas), a group of low- to intermediate-grade invasive mammary carcinomas with discohesive, diffusely infiltrative cells showing retained circumferential membranous immunoreactivity for both E-cadherin and p120. We analyzed the clinical-pathologic features of 166 LLIMCas compared to 104 classical invasive lobular carcinomas (ILCs) and 100 grade 1 and 2 invasive ductal carcinomas (IDCs). Tumor size and pT stage of LLIMCas were intermediate between IDCs and ILCs, and yet often underestimated on imaging and showed frequent positive margins on the first resection. Despite histomorphologic similarities to classical ILC, the discohesion in LLIMCa was independent of E-cadherin/p120 immunophenotypic alteration. An exploratory, hypothesis-generating analysis of the genomic features of 14 randomly selected LLIMCas and classical ILCs (7 from each category) was performed utilizing an FDA-authorized targeted capture sequencing assay (MSK-IMPACT). None of the seven LLIMCas harbored CDH1 loss-of-function mutations, and none of the CDH1 alterations detected in two of the LLIMCas was pathogenic. In contrast, all seven ILCs harbored CDH1 loss-of-function mutations coupled with the loss of heterozygosity of the CDH1 wild-type allele. Four of the six evaluable LLIMCas were positive for CDH1 promoter methylation, which may partially explain the single-cell infiltrative morphology seen in LLIMCa. Further studies are warranted to better define the molecular basis of the discohesive cellular morphology in LLIMCa. Until more data becomes available, identifying LLIMCas and distinguishing them from typical IDCs and ILCs would be justified. In patients with LLIMCas, preoperative MRI should be entertained to guide surgical management.

Androgen receptor amplification in mesonephric remnants

Mesonephric remnants (MRs) are embryonic vestiges most commonly found in female pathology specimens from the lateral wall of the cervix. The highly regulated genetic programme of mesonephric duct development has been well characterised in animals based on traditional surgical castration and knockout mouse experiments. However, the process is incompletely understood in humans. MRs are believed to give rise to mesonephric neoplasms, which are rare tumours with uncertain pathophysiology. There is a dearth of molecular studies on mesonephric neoplasms in part due to their rarity. Here, we report the results of next-generation sequencing of MR, which identified amplification of the androgen receptor gene for the first time to the best of our knowledge and discuss the potential implications in the context of the literature.

Extrauterine Mesonephric-like Carcinoma: A Comprehensive Single Institution Study of 33 Cases

Extrauterine mesonephric-like carcinoma (ExUMLC) shares histologic, immunohistochemical (IHC), and molecular (MOL) features with endometrial mesonephric-like carcinoma (EnMLC). Its rarity and histologic overlap with Mullerian carcinomas contribute to underrecognition of ExUMLC. Aggressive behavior of EnMLC is well-documented; behavior of ExUMLC is yet to be characterized. This study presents the clinicopathologic, IHC, and MOL features of 33 ExUMLC identified over a 20-year time period (2002-2022) and compares the behavior of this cohort to more common upper gynecologic Mullerian carcinomas (low-grade endometrioid, LGEC; clear cell, CCC; high-grade serous, HGSC) and EnMLC diagnosed over the same time period. ExUMLC patients ranged from 37 to 74 years old (median=59 y); 13 presented with advanced stage (FIGO III/IV) disease. Most ExUMLC had the characteristic mixture of architectural patterns and cytologic features, as previously described. Two ExUMLC had sarcomatous differentiation, 1 with heterologous rhabdomyosarcoma. Twenty-one ExUMLC (63%) had associated endometriosis, and 7 (21%) arose in a borderline tumor. In 14 (42%) cases, ExUMLC was part of a mixed carcinoma representing >50% of the tumor in 12. Twenty-six cases (79%) were incorrectly classified as follows: LGEC or HGEC (12); adenocarcinoma, not otherwise specified (3); HGSC (3); LGSC (2); mixed carcinoma (1); carcinosarcoma, Mullerian type (2); seromucinous carcinoma (1); transitional pattern of HGSC (1); and female adnexal tumor of probable Wolffian origin (1). Three patients had occult synchronous endometrial LGEC. IHC facilitated diagnosis in all cases with an expression of GATA-3 and/or TTF-1 in conjunction with decreased hormone receptor expression in most tumors. MOL testing (n=20) identified a variety of mutations, most frequently: KRAS (15); TP53 (4); SPOP (4); and PIK3CA (4). ExUMLC and CCC were more likely to be associated with endometriosis ( P <0.0001). ExUMLC and HGSC had more recurrences compared with CCC and LGEC ( P <0.0001). Histologic subtype was associated with longer disease-free survival for LGEC and CCC versus HGSC and ExUMLC ( P <0.001). ExUMLC trended towards a similar poor overall survival as HGSC compared with LGEC and CCC, and EnMLC trended to shorter survival compared with ExUMLC. Neither finding reached significance. No differences were seen between EnMLC and ExUMLC with respect to presenting stage or recurrence. Staging, histotype, and endometriosis were associated with disease-free survival, but on multivariate analysis, only stage remained as an independent predictor of outcome. The tendency of ExUMLC to present at an advanced stage and have distant recurrence points to more aggressive behavior compared with LGEC with which it is most frequently confused, underscoring the importance of an accurate diagnosis.

p53 and ovarian carcinoma survival: an Ovarian Tumor Tissue Analysis consortium study

Our objective was to test whether p53 expression status is associated with survival for women diagnosed with the most common ovarian carcinoma histotypes (high-grade serous carcinoma [HGSC], endometrioid carcinoma [EC], and clear cell carcinoma [CCC]) using a large multi-institutional cohort from the Ovarian Tumor Tissue Analysis (OTTA) consortium. p53 expression was assessed on 6,678 cases represented on tissue microarrays from 25 participating OTTA study sites using a previously validated immunohistochemical (IHC) assay as a surrogate for the presence and functional effect of TP53 mutations. Three abnormal expression patterns (overexpression, complete absence, and cytoplasmic) and the normal (wild type) pattern were recorded. Survival analyses were performed by histotype. The frequency of abnormal p53 expression was 93.4% (4,630/4,957) in HGSC compared to 11.9% (116/973) in EC and 11.5% (86/748) in CCC. In HGSC, there were no differences in overall survival across the abnormal p53 expression patterns. However, in EC and CCC, abnormal p53 expression was associated with an increased risk of death for women diagnosed with EC in multivariate analysis compared to normal p53 as the reference (hazard ratio [HR] = 2.18, 95% confidence interval [CI] 1.36-3.47, p = 0.0011) and with CCC (HR = 1.57, 95% CI 1.11-2.22, p = 0.012). Abnormal p53 was also associated with shorter overall survival in The International Federation of Gynecology and Obstetrics stage I/II EC and CCC. Our study provides further evidence that functional groups of TP53 mutations assessed by abnormal surrogate p53 IHC patterns are not associated with survival in HGSC. In contrast, we validate that abnormal p53 IHC is a strong independent prognostic marker for EC and demonstrate for the first time an independent prognostic association of abnormal p53 IHC with overall survival in patients with CCC.

Ovarian Combined Serous Borderline Tumor/Low-grade Serous Carcinoma and Mesonephric-like Lesion: Report of 2 Cases With New Observations

Ovarian combined serous borderline tumor/low-grade serous carcinomas (SBT/LGSC) and mesonephric-like adenocarcinomas (MLA) have been previously reported and the presence of identical oncogenic somatic mutations in both components supports the concept that at least some of MLAs arise from a Müllerian origin. We report 2 cases of ovarian combined SBT/LGSC and mesonephric-like lesion. Case 1 was a 70-yr-old woman presented with a liver lesion and omental carcinomatosis. Histologic examination revealed biphasic tumors in bilateral ovaries consisting of conventional SBT and invasive MLA with extraovarian spread. The right ovary also had a component of cribriform variant of SBT/noninvasive LGSC. The SBT/LGSC component was diffusely positive for Pax8, WT-1, and ER, focally positive for PR, and negative for GATA3, while the MLA component was diffusely positive for GATA3 but negative for WT-1, ER, and PR. Molecular analysis revealed a KRAS G12V mutation in both the SBT/LGSC and MLA components, indicating their clonal origin. Case 2 was a 58-yr-old woman who presented with conventional type SBT in both ovaries. In addition, the left ovarian tumor demonstrated a few areas (each <5 mm) of mesonephric-like differentiation/hyperplasia in close proximity to the serous-type epithelium, with an immunophenotype of focal GATA3 expression, luminal pattern of CD10 staining and negative WT-1, ER, and PR staining. This phenomenon has been reported in endometrioid borderline tumor but not in any serous type lesions. The findings in case 1 provide further evidence to demonstrate the clonal relationship between these morphologically and immunophenotypically distinct components. It also supports the theory that, unlike cervical mesonephric carcinomas originating from mesonephric remnants, MLAs are derived from a Müllerian-type lesion with differentiation into mesonephric lineage. The presence of a hyperplastic mesonephric-like lesion/differentiation in case 2 indicates that a precursor lesion in the same lineage with the potential to develop into MLA exists in the ovary.

Cytological features of mesonephric-like adenocarcinoma of the uterine corpus

BACKGROUND

Although several studies have documented the histological features of uterine mesonephric-like adenocarcinoma (MLA), its cytological features have been rarely reported.

METHODS

We searched for histologically confirmed uterine MLA cases in the pathology archives of three institutions between 2010 and 2021. All available cytology slides were examined to identify the cytological features of uterine MLA.

RESULTS

We included 16 patients with uterine MLA and reviewed the slides obtained from 21 cytology samples. Samples were obtained from the cervicovagina (9/21, 42.9%), peritoneal washing (8/21, 38.1%), pleural effusion (2/21, 9.5%), and transbronchial needle aspiration of mediastinal lymph node (2/21, 9.5%). Preparation methods included ThinPrep (11/21, 52.4%), SurePath (8/21, 38.1%), and conventional smear (2/21, 9.5%). Regardless of the sampling site and preparation method, cytology samples displayed tight three-dimensional cellular clusters showing monotonous, small-to-medium-sized, round, hyperchromatic nuclei, indistinct nucleoli, scant cytoplasm, and high nuclear-to-cytoplasmic ratio. Approximately half of the samples (10/21, 47.6%) showed hyaline-like globules. Mitotic figures (7/21, 33.3%) and apoptotic bodies (13/21, 61.9%) were also observed. No tumor diathesis or nuclear feathering was identified.

CONCLUSIONS

Irrespective of sampling site and preparation method, the majority of uterine MLA cases showed the following cytological features: tight three-dimensional cellular clusters showing small-to-medium-sized, round, hyperchromatic nuclei with indistinct nucleoli and high nuclear-to-cytoplasm ratio. In case a cytology sample suspicious of a glandular lesion displays these cytological features, which are distinct from those of endocervical adenocarcinoma, uterine MLA should be included in the differential diagnosis.

High-Sensitivity Mutation Analysis of Cell-Free DNA for Disease Monitoring in Endometrial Cancer

PURPOSE

We sought to determine whether sequencing analysis of circulating cell-free DNA (cfDNA) in patients with prospectively accrued endometrial cancer captures the mutational repertoire of the primary lesion and allows for disease monitoring.

EXPERIMENTAL DESIGN

Peripheral blood was prospectively collected from 44 newly diagnosed patients with endometrial cancer over a 24-month period (i.e., baseline, postsurgery, every 6 months after). DNA from the primary endometrial cancers was subjected to targeted next-generation sequencing (NGS) of 468 cancer-related genes, and cfDNA to a high-depth NGS assay of 129 genes with molecular barcoding. Sequencing data were analyzed using validated bioinformatics methods.

RESULTS

cfDNA levels correlated with surgical stage in endometrial cancers, with higher levels of cfDNA being present in advanced-stage disease. Mutations in cfDNA at baseline were detected preoperatively in 8 of 36 (22%) patients with sequencing data, all of whom were diagnosed with advanced-stage disease, high tumor volume, and/or aggressive histologic type. Of the 38 somatic mutations identified in the primary tumors also present in the cfDNA assay, 35 (92%) and 38 (100%) were detected at baseline and follow-up, respectively. In 6 patients with recurrent disease, changes in circulating tumor DNA (ctDNA) fraction/variant allele fractions in cfDNA during follow-up closely mirrored disease progression and therapy response, with a lead time over clinically detected recurrence in two cases. The presence of ctDNA at baseline (P < 0.001) or postsurgery (P = 0.014) was significantly associated with reduced progression-free survival.

CONCLUSIONS

cfDNA sequencing analysis in patients with endometrial cancer at diagnosis has prognostic value, and serial postsurgery cfDNA analysis enables disease and treatment response monitoring. See related commentary by Grant et al., p. 305.