SATB2 is a supportive marker for the differentiation of a primary mucinous tumor of the ovary and an ovarian metastasis of a low-grade appendiceal mucinous neoplasm (LAMN): A series of seven cases

Mucinous neoplasm of the appendix: A case report and review of literature

BACKGROUND

Appendiceal mucinous neoplasms (AMNs), although not classified as rare, are relatively uncommon tumors most often discovered incidentally during colorectal surgery. Accurate identification of AMNs is difficult due to non-specific symptoms, overlapping tumor markers with other conditions, and the potential for misdiagnosis. This underscores the urgent need for precision in diagnosis to prevent severe complications.

CASE SUMMARY

This case report describes the unexpected discovery and treatment of a low-grade AMN (LAMN) in a 74-year-old man undergoing laparoscopic hemicolectomy for transverse colon adenocarcinoma (AC). Preoperatively, non-specific gastrointestinal symptoms and elevated tumor markers masked the presence of AMN. The tumor, presumed to be an AMN peritoneal cyst intraoperatively, was confirmed as LAMN through histopathological examination. The neoplasm exhibited mucin accumulation and a distinct immunohistochemical profile: Positive for Homeobox protein CDX-2, Cytokeratin 20, special AT-rich sequence-binding protein 2, and Mucin 2 but negative for cytokeratin 7 and Paired box gene 8. This profile aids in distinguishing appendiceal and ovarian mucinous tumors. Postoperative recovery was uncomplicated, and the patient initiated adjuvant chemotherapy for the colon AC.

CONCLUSION

This case highlights the diagnostic complexity of AMNs, emphasizing the need for vigilant identification to avert potential complications, such as pseudomyxoma peritonei.

Global trends in research of pseudomyxoma peritonei: a bibliometric and visualization analysis

Objective

Pseudomyxoma peritonei (PMP) was a complex disease that had attracted increasing attention. However, there had been no bibliometric analysis of this disease so far. This study aimed to explore the current situation and frontier trend of PMP through bibliometric and visualization analysis, and to indicate new directions for future research.

Methods

The original research articles and reviews related to the PMP research were downloaded from Web of Science Core Collection on September 11, 2023. CiteSpace (6.2.R4) and VOSviewer(1.6.18) were used to perform bibliometric analysis of the publications, and establish the knowledge map. The data collected was analyzed using the Online Analysis Platform of Bibliometric to evaluate the cooperation of countries in this field.

Results

We identified 1449 original articles and reviews on PMP published between 1998 and 2023. The number of publications on PMP increased continuously. The United States, the United Kingdom and China were the top contributors. The most productive organization was the MedStar Washington Hospital Center. Sugarbaker, Paul H. was the most prolific author and the most cited. Keyword analysis showed that "Pseudomyxoma peritonei", "cancer", "cytoreductive surgery", and "hyperthermic intraperitoneal chemotherapy" were the most common keywords. The earliest and latest used keywords were "mucinous tumors" and "impact", respectively. "classification", "cytoreductive surgery", "appendiceal" were the top 3 strongest citation bursts. The reference "Carr NJ, 2016, AM J SURG PATHOL" had the highest co-citations.

Conclusion

This bibliometric analysis showed an increasing trend in literature related to PMP. The research trends and hotspots identified in this study could guide the future research directions in this field, in order to promote the development of PMP.

Updates in the Use of Immunohistochemical Stains in Breast and Gynecologic Pathology

CONTEXT.—

The use of immunohistochemical stains in breast and gynecologic pathology has become increasingly complex, with various diagnostic, prognostic, and predictive applications.

OBJECTIVE.—

To provide an update and review of immunohistochemical stains used in the practice of breast and gynecologic pathology. Established and new entities are reviewed, with descriptions of histomorphology and immunohistochemical staining patterns and discussion of interpretive pitfalls.

DATA SOURCES.—

Data were obtained from review of the English-language literature and firsthand experience of the authors in breast and gynecologic pathology.

CONCLUSIONS.—

Many entities in breast and gynecologic pathology benefit from evaluation with various immunohistochemical stains. These studies not only aid in the diagnosis and staging of tumors but also can provide prognostic and predictive information. Updated guidelines for recommended ancillary studies such as mismatch repair, p53, and human epidermal growth factor receptor 2 (HER2) studies in endometrium, as well as estrogen and progesterone receptors and HER2 in breast, are discussed. Finally, the use and interpretation of established and novel immunohistochemical stains are discussed in various breast and gynecologic malignancies.

Evaluation of Lineage/Site-specific Nuclear Immunohistochemical Markers SATB2, Cyclin D1, SALL4, and BCOR in High-grade Endometrial Carcinomas

Poorly differentiated malignant neoplasms involving the gynecologic tract routinely include a poorly differentiated endometrial carcinoma (EC) in the differential diagnosis. Some nuclear lineage/site-specific immunohistochemical markers are utilized in this diagnostic setting including SATB2, cyclin D1, SALL4, and BCOR, but their specificity and use in small samples are not clear across the spectrum of ECs. Cases of undifferentiated/dedifferentiated endometrial carcinomas (UEC/DDEC), clear cell carcinoma (CCC), uterine serous carcinoma (USC), FIGO grade 3 endometrial endometrioid carcinoma (EEC), and uterine carcinosarcoma (UCS) were identified and diagnoses confirmed. Whole-section immunohistochemical stains for SATB2, cyclin D1, SALL4, BCOR, and PAX8 were performed. A total of 113 cases were utilized: 15 CCC, 26 EEC, 19 UCS, 22 USC, and 31 UEC/DDEC. Cases were distributed across both low (49%) and high (51%) FIGO clinical stages. SATB2 was expressed by UCS (8/19, 42%), EEC (10/26, 38%), UEC/DDEC (11/30, 37%), and USC (6/22, 27%). Cyclin D1 was expressed by EEC (24/26, 92%), USC (17/22, 77%), UEC/DDEC (15/20 EEC component, 75%; 22/30 UEC, 73%), UCS (10/16 carcinoma, 63%; 11/19 sarcoma, 58%), and CCC (8/15, 53%). SALL4 was expressed most frequently by UEC/DDEC (12/30, 40%), but also USC (7/22, 32%), EEC (5/26, 19%), and UCS (4/16 carcinoma, 25%; 3/19 sarcoma, 16%). BCOR was expressed at low levels in 2 USC, 2 UEC/DDEC, and 2 UCS. PAX8 was generally positive but showed lower expression in UEC/DDEC (17/30, 57%) and in the sarcomatous portions of UCS (6/19, 32%). SATB2, cyclin D1, SALL4, and BCOR stain variable numbers of poorly-differentiated EC and must be carefully interpreted within morphologic and clinical context.

A combination of immunohistochemical markers, MUC1, MUC5AC, PAX8 and growth pattern for characterization of mucinous neoplasm of the ovary

OBJECTIVE

Because mucinous carcinomas are rare tumors that affect several organ sites and are known to originate from different tissues, leading to frequent misdiagnoses, the objective was to characterize the differences between primary mucinous tumors of the ovary and metastatic mucinous cancer to the ovary by studying the expression pattern of several candidate biomarkers.

METHODS

Tissue samples of mucinous histology were obtained between 1985 and 2015. Individual ovary and colon tissue samples were analyzed, including standard (PAX8, CK20, CK7, CDX2, SATB2, estrogen/progesterone) and new (MUC1, MUC5AC) biomarkers, which were then scored for immunoreactivity semi-quantitatively.

RESULTS

The study cohort included 98 mucinous tumor samples, including benign mucinous cystadenoma (n=24), mucinous borderline tumors (n=24), mucinous carcinomas (n=40), and metastatic mucinous ovarian carcinomas (n=10). A strong positive correlation was found between PAX8 scoring (p=0.003), CK7 scoring (p=0.0001), and MUC1 scoring (p=0.001) in primary mucinous ovarian cancer. Tumors of increasing invasiveness were analyzed and a significant decrease in the scoring of MUC5AC (p=0.001) was observed, with a stronger expression in adenomas (87%) and borderline tumors (75%), and a lower expression in mucinous cancers (42%). Patients survived significantly longer when their tumors expressed high PAX8 and showed an expansile invasion pattern (p=0.005 and p=0.015, respectively) compared with patients with PAX8-negative tumors and destructive invasion pattern.

CONCLUSION

The study data support the diagnostic value of MUC1 as a new biomarker to differentiate between primary and metastatic mucinous ovarian cancer. In addition, the tumor growth pattern along with the PAX8 immunophenotype might represent potential prognostic biomarkers for primary mucinous ovarian carcinomas.

Gynaecological or gastrointestinal origin? Recognising Müllerian neoplasms with gastrointestinal phenotype and determining the primary site in selected entities

Recognising metastatic gastrointestinal and pancreatobiliary tumours to gynaecological sites may be challenging, as primary Müllerian tumours can demonstrate similar histological features. Endocervical adenocarcinomas can be of gastric and intestinal types, endometrial lesions may show gastrointestinal phenotype, and finally, mucinous tumours with secondary involvement of the ovaries may mimic primary neoplasms. The aim of this review is to address selected neoplastic entities of the gynaecological tract with gastric and intestinal differentiation and provide helpful clinical and pathological parameters for the diagnosis. A brief overview of metastatic tumours originating from the gastrointestinal and pancreaticobiliary tracts is also provided, including the most common pathological features.

Primary mucinous ovarian tumors vs. ovarian metastases from gastrointestinal tract, pancreas and biliary tree: a review of current problematics

Background

Making the distinction between primary mucinous and metastatic ovarian tumors is often difficult, especially in tumors with a primary source from the gastrointestinal tract, pancreas and biliary tree. The aim of the following paper is to provide an overview of the problematics, with a focus on the possibilities of the differential diagnosis at the macroscopic, microscopic and immunohistochemical level.

Main body

The three main aspects of mucinous ovarian tumors are described in detail, including the comparison of the available diagnostic algorithms based on the evaluation of mostly macroscopic features, characterization of the spectrum of microscopic features, and a detailed analysis of the immunophenotype comparing 20 antibodies with the assessment of their statistical significance for differential diagnosis purposes. Specific features, including Krukenberg tumor and pseudomyxoma peritonei, are also discussed.

Conclusion

Despite the growing knowledge of the macroscopic and microscopic features of ovarian mucinous tumors and the availability of a wide range of immunohistochemical antibodies useful in this setting, there still remains a group of tumors which cannot be precisely classified without close clinical-pathological cooperation.

Immunohistochemistry features and molecular pathology of appendiceal neoplasms

Primary appendiceal neoplasms (ANs) comprise a heterogeneous group of tumors. The pathology and classification of ANs have been controversial, and thus, a new classification of these neoplasms was published in the World Health Organization (WHO) classification of tumors (5th edition, 2019). However, immunohistochemistry (IHC) features of epithelial ANs are not explained in this edition and the limited data on the molecular pathology of these tumors shows inconsistent findings in various studies. It would be useful to identify biomarkers appropriate for each subtype to better aid in treatment selection. Therefore, we reviewed the literature to investigate what is known of the molecular pathology and IHC features of the most frequently diagnosed pathological subtypes of epithelial ANs based on the recent classification. The inconsistencies in research findings regarding the IHC features and molecular pathology of ANs could be due to differences in the number of samples and their collection and preparation as well as to the lack of a universally accepted classification system for these neoplasms. However, the literature shows that epithelial ANs typically stain positive for MUC2, CK20, and CDX2 and that the expression of SATB2 protein could be used as a biomarker for appendix tumor origin. Low-grade appendiceal mucinous neoplasms tend to have mutations in KRAS and GNAS but are usually wild-type for BRAF, APC, and P53. Conversely, appendiceal adenocarcinomas are frequently found with mutations in KRAS, GNAS, P53, PIK3CA, and APC, and have significant nuclear expression of β-catenin, loss of nuclear or nuclear and cytoplasmic expression of SMAD4, and loss of cytoplasmic membranous expression of E-cadherin. Goblet cell carcinomas (GCCs) typically stain positive for keratin and mucin markers and are frequently mutated in P53 and chromatin-modifier genes, but they tend to be wild-type for KRAS, GNAS, APC, and PIK3CA. The expression of CK7 and SATB2 proteins is usually negative in appendiceal neuroendocrine neoplasms and they lack the mutations in common cancer-associated genes including APC, BRAF, SMAD4, and PIK3C. The available data suggest that GCCs have distinct molecular and immunohistochemical features and that they have characteristics more in common with adenocarcinoma than classical neuroendocrine tumors. In addition, MSI does not seem to have a role in the pathogenesis of epithelial ANs because they are rarely detected in these tumors. Finally, hereditary predisposition may have a role in the development of ANs because heterozygous CTNNβ1, NOTCH1, and NOTCH4 germline mutations have recently been identified in low and high grades ANs.

SATB2 in Neoplasms of Lung, Pancreatobiliary, and Gastrointestinal Origins

OBJECTIVES

Special AT-rich binding protein 2 (SATB2) immunohistochemistry (IHC) has high sensitivity and specificity for colorectal adenocarcinoma (CRC), but data on its expression in specific subsets of pulmonary, gastric, small bowel, and pancreatobiliary adenocarcinomas (ADCAs) are relatively limited or discordant. We assessed SATB2 expression in a large cohort of ADCAs from these sites to determine its reliability in distinguishing CRC from them.

METHODS

SATB2 IHC was performed on 335 neoplasms, including 40 lung ADCAs, 165 pancreatobiliary neoplasms (34 intraductal papillary mucinous neoplasms [IPMNs], 19 pancreatic ADCAs, 112 cholangiocarcinomas [CCs]), and 35 gastric, 13 small bowel, 36 ampullary (AMP), and 46 CRC ADCAs. The cases were evaluated for positivity (defined as ≥5% nuclear staining), and an H-score was calculated based on the percentage of SATB2+ cells and staining intensity. Analysis was performed to determine the optimal H-score threshold to separate CRC and non-CRC.

RESULTS

SATB2 was positive in 3% of lung, 2% of CC, 17% of gastric, 38% of small bowel, and 6% of AMP ADCAs. All pancreatic ADCA/IPMNs were negative, and 87% CRCs were positive.

CONCLUSIONS

SATB2 is not entirely specific for colorectal origin and can be expressed in a subset of gastrointestinal ADCAs. It is most useful in the differential of CRC vs lung and pancreatobiliary ADCAs.

Gross mucinous multinodular appearance aids in the identification of ovarian metastases in low-grade appendiceal mucinous neoplasms during intraoperative consultation

Ovarian metastases of low-grade appendiceal mucinous neoplasms (LAMNs) show grossly abundant nodular mucous cells, with a gross mucinous multinodular appearance and a histological resemblance to primary ovarian mucinous tumors (POMTs). This study aimed to elucidate the utility of gross features including the gross mucinous multinodular appearance and available clinical information at the time of intraoperative consultation, in distinguishing the ovarian metastases of LAMNs from POMTs or the ovarian metastases of colorectal cancer (CRC). In total, 776 patients with primary ovarian tumor and 68 patients with ovarian metastases underwent intraoperative consultation during 1998-2018. Of the total cases, 4 ovarian metastases of LAMNs, 19 ovarian metastases of CRC, and 50 POMTs (36 borderline tumors and 14 carcinomas) were identified. The gross features including the gross mucinous multinodular appearance were analyzed based on the gross photographs obtained before formalin fixation and the available clinical information collected during intraoperative consultation. The analysis indicated that the ovarian metastases of LAMNs significantly presented with gross mucinous multinodular appearance (4/4 vs. 0/50, P < 0.0001), extraovarian disease (4/4 vs. 2/50, P < 0.0001), ovarian surface involvement (3/4 vs. 2/50, P = 0.0016), and abnormal appendix (4/4 vs. 0/50, P < 0.0001) as compared to POMT. Moreover, the gross mucinous multinodular appearance was a distinguishable feature between the ovarian metastases of LAMNs and ovarian metastases of CRC (4/4 vs. 0/19, P = 0.0001). Based on these results, we proposed an algorithm to diagnose ovarian tumors using the gross mucinous multinodular appearance. Thus, recognizing unique gross features including the gross mucinous multinodular appearance would be useful for both pathologists and surgeons to accurately diagnose ovarian metastases of LAMNs during intraoperative consultation.

Multi-origin mucinous neoplasm: Should we prophylactically remove the appendix in the setting of mucinous ovarian tumors?

INTRODUCTION

Tumors of the ovary and appendix have been well documented in the setting of pseudomyxoma peritonei (PMP) with constant debate over tumor origin. Generally, these tumors are found to have a single primary origin, most commonly the appendix, with metastatic spread to the ovaries.

CARE PRESENTATION

Here we present a 61-year-old female who underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO) for a primary mucinous ovarian carcinoma. She presented to our institution one year later with abdominal pain and a palpable right lower quadrant mass, which on histopathologic exam was found to be a primary low grade mucinous appendiceal neoplasm (LAMN), alluding to the potential of two separate primary disease processes.

DISCUSSION/CONCLUSION

With two primary, non-synchronous lesions, a thorough literature review suggests that during the patient's initial TAH-BSO, she could have additionally undergone an appendectomy. In doing so, this would provide accurate, complete staging and determine if the two neoplasms were truly primary in origin or metastatic. In addition, new genetic markers are being discovered, such as the Special AT-rich sequence-binding protein 2 (SATB2) marker, which has been found to be positive in those with a LAMN and negative in those with a primary mucinous ovarian carcinoma. By acquiring appropriate and complete staging we can better diagnose and treat these neoplasms.

[Pitfalls and common problems in the differential diagnosis of epithelial ovarian tumors]

Epithelial ovarian tumors may cause various diagnostic problems of practical relevance. For the distinction between cystadenomas and borderline tumors/atypically proliferative tumors, a minimum extent of 10% of the atypical epithelial proliferation has been suggested by the WHO. The micropapillary variant of serous borderline tumors is more frequently associated with invasive growth and extraovarian lesions. Extraovarian lesions of borderline tumors are relevant for prognosis and cause a higher stage; their classification is crucial. Traditionally, they were classified into noninvasive and invasive implants based on their morphology. Based on the 2014 WHO classification, invasive lesions should be designated as low-grade serous carcinomas whereas only noninvasive lesions are considered implants. The most frequent invasive growth pattern in low-grade serous carcinomas consists of haphazardly arranged tumor cell nests and small papillae in clefts, whereas mucinous and endometrioid carcinomas mainly show a confluent glandular pattern with maze-like and cribriform structures. For metastatic mucinous tumors a nodular growth pattern is characteristic; ruling them out requires clinical information including imaging and immunohistochemistry. Differential diagnosis between low-grade and high-grade serous carcinoma is based on the degree of nuclear polymorphism and mitotic count. The seromucinous tumor category replaces the endocervical subtype of mucinous tumors and resembles histologically, biologically, and on the molecular level serous and endometrioid tumors. Endometrioid tumors with fibromatous stroma need to be distinguished from tumors with Sertoli cell differentiation and well-differentiated neuroendocrine tumors. For differential diagnosis of epithelial ovarian tumors, in particular carcinomas, a panel of antibodies for immunohistochemistry is very useful under consideration of histomorphology.

Mucinous Ovarian Tumors

Ovarian mucinous tumors range from benign cystadenomas to borderline tumors to frankly malignant adenocarcinomas, and may display either intestinal-type morphology or, less frequently, endocervical-type differentiation. The latter category has been the subject of recent controversy owing to its morphologic overlap with so-called "seromucinous" ovarian tumors, a group that shares more molecular features with endometrioid tumors than it does with either serous or mucinous ovarian neoplasias. Endocervical-type differentiation in ovarian mucinous tumors may also represent an endocervical metastasis. Distinction of primary ovarian mucinous tumors from gastrointestinal metastases can be difficult, as the morphology of intestinal-type ovarian mucinous primaries sometimes differs only subtly if at all from gastrointestinal metastases.