Immunophenotype of Atypical Polypoid Adenomyoma of the Uterus: Diagnostic Value and Insight on Pathogenesis

Stromal p16 and SATB2 Expression Does Not Distinguish Atypical Polypoid Adenomyoma (APA) From its Benign Mimics

Atypical polypoid adenomyoma (APA) is a polypoid biphasic lesion of low malignant potential that arises in the lower uterine segment and uterine corpus. The diagnosis of APA is often challenging on biopsy and curettage specimens, and both benign and malignant processes need to be considered in the differential. Stromal expression of p16 and SATB2 have recently been shown to distinguish APA from myoinvasive endometrioid carcinoma. The authors hypothesized that p16 and SATB2 immunohistochemistry could also aid in the distinction of APA from benign adenomyomatous polyp and endometrioid adenomyoma. The study comprised 10 APAs, 7 adenomyomatous polyps, 11 endometrioid adenomyomas, and 10 myoinvasive endometrioid carcinomas. The majority of APAs showed moderate to strong, diffuse p16 and stromal expression. However, most adenomyomatous polyps and endometrioid adenomyomas also exhibited moderate to strong, focal to diffuse p16 stromal expression. SATB2 showed weak to moderate, focal to diffuse expression in the majority of APAs, adenomyomatous polyps and endometrioid adenomyomas. In contrast, p16 and SATB2 were negative to weak and focal in 90% of myoinvasive endometrioid carcinomas. Our findings demonstrate that p16 and SATB2 may be helpful in the differential diagnosis of myoinvasive endometrioid carcinoma and APA while not useful in separating APA from adenomyomatous polyp and endometrioid adenomyoma.

Prolapsed Atypical Polypoid Adenomyoma-A Case Report and Literature Review

Atypical polypoid adenomyoma (APAM) is a rare polypoid benign tumor of the uterus that causes irregular vaginal bleeding in women of reproductive age. It has the potential for malignant transformation, but it does not metastasize. APAM may coexist with endometrial hyperplasia and adenocarcinoma, usually leading to misdiagnosis. Histopathologically, it is a biphasic tumor, represented by the endometrioid glands with a complex histoarchitecture, with sometimes squamous morular metaplasia or cytologic atypia, interspersed with a fibromyomatous stroma. This tumor has a high incidence of recurrence. We present a very rare case of a 21-year-old patient, a virgin, without a significant medical history, with a bleeding mass occupying the vagina. The mass was excised using forceps, scissors, and a suture of the visible pedicle. After a four-year follow-up and no additional medical treatment, no relapse was observed. Given the risk of recurrence and progression, APAM might be treated via a hysterectomy in patients with no desire for pregnancy. Due to a lower recurrence rate, the conservative treatment of atypical polypoid adenomyoma performed via an operative hysteroscopy represents the best choice. Previously diagnosed in hysterectomy specimens, with the introduction of better-performing indirect imaging techniques, adenomyosis is a clinical entity that has the possibility of being diagnosed in the presurgical stage.

A Clinicopathological Review of 203 Cases of Atypical Polypoid Adenomyoma of the Uterus

OBJECTIVE

To provide a reference for the diagnosis and treatment of atypical polypoid adenomyoma (APA).

METHODS

This was a retrospective study of 203 APA patients from 2011 to 2021. The clinicopathological characteristics, treatments, and prognosis were analyzed.

RESULTS

The average age at diagnosis of APA patients was 39.30 ± 11.01 years, and premenopausal women accounted for 81.3%. Abnormal uterine bleeding or menorrhagia were the most common clinical manifestations of APA. The uterine fundus (78.3%), followed by the lower segment of the uterus (11.8%), was the most common location of the APA lesions. Abnormal blood vessels were seen on the surface of 28 APA tumors. APA can coexist with atypical endometrial hyperplasia (18.2%) and endometrial cancer (10.8%). Immunohistochemical analysis was performed on 99 samples. In the glandular component, ER (94.8%), PR (94.8%), Ki-67 (51.5%), p53 (45.6%), PTEN (18.8%), and mismatch repair proteins (96.4%) were positively expressed. Stromal immunophenotype expression was exhibited as follows: CD10-(89.5%), p16+(86.9%), h-caldesmon-(66.7%), Desmin+(75%), and Vimentin+(88.9%). Fifty-five APA patients received TCR, and 33 of them received adjuvant therapy after the operation. The postoperative recurrence rate (9.1% vs. 36.4%, p < 0.05) and malignant transformation rate (3.0% vs. 18.2%, p < 0.05) of the treated group were significantly lower than the untreated group.

CONCLUSIONS

APA usually occurs in women of childbearing age, and the diagnosis is based on pathological morphology. APA has a low malignant potential, and those who have fertility requirements can undergo conservative TCR treatment, supplemented by progesterone treatment after surgery and close follow-up. Total hysterectomy is the treatment of choice for APA patients with atypical endometrial hyperplasia around the lesion.

Prognostic significance of CTNNB1 mutation in early stage endometrial carcinoma: a systematic review and meta-analysis

Background

In the last years, mutations in the exon 3 of CTNNB1 have emerged as a possible prognostic factor for recurrence in early stage endometrioid endometrial carcinoma, especially in cases with no specific molecular profile (NSMP).

Objective

To define the prognostic value of CTNNB1 mutations in early stage endometrioid endometrial carcinoma, through a systematic review and meta-analysis.

Methods

Electronic databases were searched from their inception to November 2020 for all studies assessing the prognostic value of CTNNB1 mutation in early stage (FIGO I–II) endometrioid endometrial carcinoma. Odds ratio (OR) for tumor recurrence and hazard ratio (HR) for disease-free survival (DFS) were calculated with a significant p value < 0.05.

Results

Seven studies with 1031 patients were included. Four studies were suitable for meta-analysis of OR and showed significant association between CTNNB1 mutation and the absolute number of recurrence (OR = 3.000; p = 0.019); the association became stronger after excluding patients with known molecular status other than NSMP (HR = 5.953; p = 0.012). Three studies were suitable for meta-analysis of HR and showed no significant association between CTNNB1 mutation and decreased DFS (HR = 1.847; p = 0.303); the association became significant after excluding patients with known molecular status other than NSMP (HR = 2.831; p = 0.026).

Conclusion

CTNNB1 mutation is significantly associated with recurrence in early stage endometrioid endometrial carcinomas, especially in the NSMP, appearing potentially useful in directing adjuvant treatment.

An Emerging Anti-p16 Antibody-BC42 Clone as an Alternative to the Current E6H4 for Use in the Female Genital Tract Pathological Diagnosis: Our Experience and a Review on p16ink4a Functional Significance, Role in Daily-Practice Diagnosis, Prognostic Potential, and Technical Pitfalls

Background: To date, useful diagnostic applications of p16 IHC have been documented in gynecological pathology both for HPV-related and non-HPV-related lesions. In the present article, we reported our experience with the novel anti-p16 INK4a antibody (clone BC42), whose expression was tested across all different gynecologic neoplasms; we also compared it to the traditional E6H4 clone. Moreover, we discussed and explored all the diagnostic applications of p16 IHC in gynecologic pathology. Methods: Consultation cases covering a 5-year period (2016–2020) regarding gynecological neoplastic and non-neoplastic lesions in which immunohistochemistry for p16, clone E6H4 was originally performed, were retrospectively retrieved from the files of our institution. Immunohistochemical staining for p16ink4a (BC42) [Biocare Medical group-Paceco USA; Bioptica Milan] and p16ink4a (E6H4) [Ventana Medical Systems-Arizona USA; Roche] was performed by using the Ventana automated immunostainer (Ventana Medical Systems, Tucson, AZ, USA). The immunostaining pattern was defined as negative, focal/patchy, or diffuse. Results: A total of 196 cases, represented by 36 high-grade SIL/CIN3 of the uterine cervix, 30 cervical adenocarcinomas, 22 cervical squamous cell carcinoma, 70 endometrial carcinomas, 25 high grade serous ovarian carcinomas, 6 uterine adenomatoid tumors, and 10 uterine leiomyosarcomas were included in this study. Results showed concordant staining quality of both clones on all tested neoplastic tissues. Conclusions: The novel anti-p16 antibody (BC42 clone) appeared as an alternative to the current E6H4 for use in gynecological neoplasms, offering similar levels of positivity and equally reliable staining results.

Patterns of SATB2 and p16 reactivity aid in the distinction of atypical polypoid adenomyoma from myoinvasive endometrioid carcinoma and benign adenomyomatous polyp on endometrial sampling

AIMS

Atypical polypoid adenomyoma (APAM) is an uncommon uterine lesion composed of complex endometrioid glands with frequent squamous morular metaplasia and fibromuscular stroma. On endometrial curettage, biopsy or polypectomy specimens, the admixture of endometrioid glands and smooth muscle raises the differential diagnosis of myoinvasive endometrioid carcinoma. Reproductive-age APAM patients may opt for fertility preservation, whereas myoinvasive carcinoma is treated surgically. One previous study reported an incidental finding that the stroma of APAM, in contrast to that of other polypoid lesions, was SATB2-positive. APAM has also been reported to show increased stromal p16 staining. We aimed to assess whether SATB2 and p16 are useful stains for the distinction of APAM from myoinvasive carcinoma and benign adenomyomatous polyps.

METHODS AND RESULTS

Cases of 'atypical polypoid adenomyoma' (n = 32), 'adenomyomatous polyp' (n = 39) and 'myoinvasive endometrioid carcinoma' (n = 30) were identified. Morphological features were assessed, along with the intensity and extent of SATB2 and p16 staining in the stromal component of each lesion. SATB2 expression was seen in the stromal components of 30 of 32 (94%) APAMs, versus none of 39 (0%) benign adenomyomatous polyps and five of 30 (17%) myoinvasive endometrioid carcinomas. Stromal p16 expression was seen in 31 of 31 (100%) APAMs, versus 20 of 39 (51%) benign adenomyomatous polyps and 12 of 30 (40%) myoinvasive endometrioid carcinomas.

CONCLUSIONS

Patchy to diffuse SATB2 and block-type p16 staining of fibromuscular stroma separating atypical endometrioid glands is more consistent with APAM than with myoinvasive endometrioid carcinoma. These stains are potentially useful adjuncts to careful morphological evaluation of endometrial biopsies/curettings.

Does endometrial morular metaplasia represent odontogenic differentiation?

The nature of endometrial morular metaplasia (MorM) is still unknown. The nuclear β-catenin accumulation and the not rare ghost cell keratinization suggest a similarity with hard keratin-producing odontogenic and hair matrix tumors rather than with squamous differentiation. We aimed to compare MorM to hard keratin-producing tumors. Forty-one hard keratin-producing tumors, including 26 hair matrix tumors (20 pilomatrixomas and 6 pilomatrix carcinomas) and 15 odontogenic tumors (adamantinomatous craniopharyngiomas), were compared to 15 endometrioid carcinomas with MorM with or without squamous/keratinizing features. Immunohistochemistry for β-catenin, CD10, CDX2, ki67, p63, CK5/6, CK7, CK8/18, CK19, and pan-hard keratin was performed; 10 cases of endometrioid carcinomas with conventional squamous differentiation were used as controls. In adamantinomatous craniopharyngiomas, the β-catenin-accumulating cell clusters (whorl-like structures) were morphologically similar to MorM (round syncytial aggregates of bland cells with round-to-spindled nuclei and profuse cytoplasm), with overlapping squamous/keratinizing features (clear cells with prominent membrane, rounded squamous formations, ghost cells). Both MorM and whorl-like structures consistently showed positivity for CD10 and CDX2, with low ki67; cytokeratins pattern was also overlapping, although more variable. Hard keratin was focally/multifocally positive in 8 MorM cases and focally in one conventional squamous differentiation case. Hair matrix tumors showed no morphological or immunophenotypical overlap with MorM. MorM shows wide morphological and immunophenotypical overlap with the whorl-like structures of adamantinomatous craniopharyngiomas, which are analogous to enamel knots of tooth development. This suggests that MorM might be an aberrant mimic of odontogenic differentiation.

TCGA Classification of Endometrial Cancer: the Place of Carcinosarcoma

In 2013, The Cancer Genome Atlas (TCGA) Research Network found four novel prognostic subgroups of endometrial carcinoma: POLE/ultramutated (POLE), microsatellite-instable/hypermutated (MSI), copy-number-low/TP53-wild-type (CNL), and copy-number-highTP53-mutant (CNH). However, poor is known regarding uncommon histotypes of endometrial cancer. We aimed to assess the genetic profile of uterine carcinosarcoma (UCS) on the light of these findings. A systematic review and meta-analysis was performed through electronic databases searching (up to July 2019). All studies assessing UCS series for the TCGA classification were included. For each TCGA subgroup, pooled prevalence on the total UCS number was calculated. Four studies with 231 patients were included. Pooled prevalence of the TCGA subgroups were: 5.3% for the POLE subgroup, 7.3% for the MSI subgroup, 73.9% for the CNH subgroup, 13.5% for the CNL subgroup. The CNH subgroup predominates in UCS, while subgroups with high mutational load (POLE and MSI) are less common. UCS appears as a preferential evolution of CNH carcinomas.

Diagnostic accuracy of p53 immunohistochemistry as surrogate of TP53 sequencing in endometrial cancer

Aberrant p53 immunohistochemical expression is used to identify the copy-number-high/TP53-mutant subgroup of endometrial cancer (EC). We aimed to determine the diagnostic accuracy of p53 immunohistochemistry as surrogate for TP53 sequencing through a systematic review and meta-analysis. Electronic databases were searched from their inception to June 2019. All studies assessing p53 expression and TP53 mutations in EC were included. Diagnostic accuracy was assessed based on area under the curve (AUC). Immunohistochemical criteria used to define aberrant p53 expression were "overexpression" and "overexpression or complete absence". Subgroup analysis was based on the sequencing technique adopted (Polymerase Chain Reaction + sequencing, or next generation sequencing, NGS). Thirteen observational studies with 727 endometrial cancers were included. Both "overexpression" and "overexpression or complete absence" showed high diagnostic accuracy (AUC = 0.9088 and 0.9030, respectively). The subgroup with "overexpression" and NGS showed the best results, with very high diagnostic accuracy (AUC = 0.9927). In conclusion, immunohistochemistry for p53 is a highly accurate surrogate of TP53 sequencing. Overexpression of p53 in ≥70-80% showed the best accuracy in predicting TP53 mutations. Further studies in this field should adopt optimized immunohistochemical procedures and take into account less common p53 patterns (e.g. cytoplasmic expression).

TCGA molecular subgroups and FIGO grade in endometrial endometrioid carcinoma

BACKGROUND

International Federation of Gynecology and Obstetrics (FIGO) grade is a crucial factor in the current system for the risk stratification of endometrial endometrioid carcinoma (EC). The Cancer Genome Atlas (TCGA) demonstrated four molecular prognostic subgroups for EC: POLE (good prognosis), microsatellite-instable (MSI, intermediate prognosis), copy-number-high (CNH, poor prognosis), and copy-number-low (CNL, variable prognosis).

OBJECTIVE

To assess how the prevalence of the TCGA molecular subgroups changes from low-grade (G1-2) to high-grade (G3) EC, to understand how it may affect the current risk-assessment system.

METHODS

A systematic review and meta-analysis was carried out by searching seven electronic databases from January 2013 to September 2019 for studies assessing the TCGA classification G1-2 and G3 EC. Pooled prevalence of the TCGA subgroups was calculated in EC. The association of each subgroup with grade was assessed using odds ratio (OR), with a significant p value < 0.05.

RESULTS

Nine studies with 3185 patients were included. G3 EC showed significantly higher prevalence of the POLE subgroup (12.1% vs 6.2%; OR = 2.13; p = 0.0001), of the MSI subgroup (39.7% vs 24.7%; OR = 2.15; p = 0.0003) and of the CNH subgroup (21.3% vs 4.7%; OR = 5.25; p < 0.00001), and significantly lower prevalence of the CNL subgroup (28% vs 63.5%; OR = 0.2; p < 0.00001) than G1-2 EC.

CONCLUSION

The prevalence of the TCGA subgroups is not in accordance with the prognostic value of FIGO grade, indicating that the current risk stratification of EC will be heavily affected by molecular signature.

TCGA Molecular Subgroups in Endometrial Undifferentiated/Dedifferentiated Carcinoma

We aimed to classify undifferentiated/dedifferentiated carcinoma (UDC/DDC) according to the four TCGA molecular subgroups of endometrial cancer: microsatellite-instable/hypermutated (MSI), POLE-mutant/ultramutated (POLE), copy-number-low/p53-wild-type (p53wt), and copy-number-high/p53-abnormal (p53abn), through a systematic review and meta-analysis. Electronic databases were searched from January 2013 to July 2019 for studies assessing the TCGA classification in endometrial UDC/DDC series. Pooled prevalence of each TCGA subgroup on the total UDC/DDCs was calculated. Three studies with 73 patients were included. Pooled prevalence of the TCGA subgroups were: 12.4% for the POLE subgroup, 44% for the MSI subgroup, 18.6% for the p53abn subgroup, 25% for the p53wt group. All TCGA groups are represented in UDC/DDC, with a predominance of the MSI group, indicating a biological heterogeneity. Hypermutated/ultramutated cancers constitute the majority of UDC/DDC, suggesting a crucial difference with other high-risk histologies of endometrial carcinoma.