Immunohistochemical findings and clinicopathological features of breast cancers with pathogenic germline mutations in Non-BRCA genes.

Deleterious germline mutations in multiple genes confer an increased breast cancer (BC) risk. Immunohistochemical (IHC) expression of protein products of mutated high-risk genes has not been investigated in BC. We hypothesized that pathogenic mutations may lead to an abnormal IHC expression pattern in the tumor cells. BCs with deleterious germline mutations in CHEK2, ATM, PALB2 & PTEN were identified. Immunohistochemistry was performed using Dako staining platform on formalin fixed paraffin embedded tumor tissue. Primary antibodies for PALB2 (ab202970), ATM [2C1(1A10)}, CHK2 (EPR4325), and PTEN (138G6) proteins were used for BCs with respective deleterious mutations. IHC expression was assessed in tumor and adjacent benign breast tissue. Total 27 BCs with 10 CHEK2, 9 ATM, 6 PALB2 & 2 PTEN deleterious germline mutations were identified. IHC staining was performed on 8 CHEK2, 7 ATM, 6 PALB2 & 2 PTEN cases. Abnormal CHEK2 IHC staining was identified in 7/8(88%) BCs. Three distinct CHK2 IHC patterns were noted: 1) Strong diffuse nuclear positivity (5 BC), 2) Null-pattern (2 BC), & 3) Normal breast-like staining in 1 BC Four of 5 (80%) strong CHK2 staining BC had missense CHEK2 mutations. Null-pattern was present with a missense & a frameshift mutation. Normal breast-like CHEK2 IHC staining pattern was present in 1 BC with CHEK2 frameshift mutation. Loss of nuclear/cytoplasmic PTEN IHC expression was noted in 2 in-situ carcinomas. Abnormal PTEN and CHK2 IHC were present in atypical ductal hyperplasia and flat epithelial atypia. ATM and PALB2 IHC expression patterns were similar in tumor cells and benign breast epithelium: mild to moderate intensity nuclear and cytoplasmic staining. We report abnormal CHEK2 IHC expression in 88% of BCs with pathogenic CHEK2 mutations. With PTEN and CHEK2 pathogenic mutations, abnormal IHC patterns are seen in early atypical proliferative lesions. IHC may be applied to identify CHEK2 & PTEN mutated BCs and precursor lesions.

Ever Expanding Morphologic Patterns of Mesonephric-like Adenocarcinomas of the Uterine Corpus: A Report of Two Tumors and a Brief Review of the Literature.

Mesonephric-like adenocarcinoma (MLA) of the endometrium shows a variety of morphologic appearances, including small glands, tubules with eosinophilic materials in the lumen, prominent papillary patterns, spindled cells, solid formations, and corded and hyalinized patterns. Unique morphology, characteristic immunohistochemical staining patterns, molecular alterations, and awareness of the pathologists make it possible to identify this tumor accurately. This report of two additional morphologic patterns, intestinal goblet cells mimicking intestinal-type mucinous carcinoma and squamous differentiation with spindle and epithelioid cells mimicking carcinosarcoma of the endometrium will expand the literature on MLA.

Human epidermal growth factor receptor-2 (HER2) expression in FIGO3 high-grade endometrial endometrioid carcinoma: Clinicopathologic characteristics and future directions.

OBJECTIVES: To study the expression of HER2 in high-grade FIGO3 endometrial endometroid carcinoma (EEC) and to correlate our findings with the clinicopathologic characteristics of this tumor. METHODS: HER2 expression by immunohistochemistry (IHC) was performed on 10% formalin-fixed paraffin embedded tissue on cases diagnosed as FIGO3 EEC. HER2 expression was interpreted as negative (0), low (1+ and 2+) or positive (3+) using similar criteria as in the breast. HER2 amplification by Fluorescence in situ hybridization (FISH) was performed on cases interpreted as 2+ and 3+ by IHC. RESULTS: One hundred and forty-three FIGO3 EEC were identified. Of these, 70 (49%) cases were HER2 negative (IHC 0), and 73 (51%) cases expressed/amplified HER2 by IHC and/or FISH. Of the 73 cases expressing or amplifying HER2, 59 cases were IHC 1+, 12 cases were IHC 2+, and 2 cases were IHC 3+. FISH testing was performed in 12 cases. Only one of the two HER2 IHC 3+ cases showed HER2 gene amplification by FISH and the other 11 cases were not amplified. The 5-year overall survival (OS) rate for HER2 IHC 1+ cases was 92.20% (95% CI: 83.97-100.00), and the 5-year OS rate for HER2 IHC 2+/3+ cases was 89.50% (95% CI: 56.41-100.00). CONCLUSION: Our findings indicate that about one half of FIGO3 EEC variably expresses HER2 and with the emerging concept of "HER2 low", anti-HER2 agents may be explored as potential therapeutic options in these patients, for possible survival benefits.

Synchronous Epidermodysplasia Verruciformis and Intraepithelial Lesion of the Vulva Is Caused by Coinfection With Alpha-Human Papillomavirus and Beta-Human Papillomavirus Genotypes and Facilitated by Mutations in Cell-Mediated Immunity Genes.

CONTEXT.­: There have been exceedingly few reports of epidermodysplasia verruciformis (EV) or EV-like lesions in the vulva. We describe the first observation of vulvar lesions displaying synchronous EV-like histology and conventional high-grade squamous intraepithelial lesion (HSIL), a finding hitherto unreported in medical literature. OBJECTIVES.­: To describe this novel vulvar lesion with hybrid features of HSIL and EV, attempt to confirm the hypothesis of coinfection with α and ß human papillomavirus (α-HPV and ß-HPV) genotypes, and describe relevant underlying genetic mutations. DESIGN.­: Cases were retrospectively selected from our institutional archive. Detailed review of clinical information, histologic examination, and whole genome sequencing (WGS) were performed. RESULTS.­: Five samples from 4 different patients were included. Three of 4 patients had a history of either iatrogenic immune suppression or prior immune deficiency, and all 3 featured classic HSIL and EV changes within the same lesion. One patient had no history of immune disorders, presented with EV-like changes and multinucleated atypia of the vulva, and was the sole patient without conventional HSIL. By WGS, several uniquely mappable reads pointed toward infection with multiple HPV genotypes, including both α-HPVs and ß-HPVs. Mutations in genes implicated in cell-mediated immunity, such as DOCK8, CARMIL2, MST1, and others, were also found. CONCLUSIONS.­: We provide the first description of vulvar lesions harboring simultaneous HSIL and EV features in the English-language literature, a phenomenon explained by coinfection with α-HPV and ß-HPV genotypes. The finding of EV-like changes in a vulvar specimen should prompt assessment of the patient's immune status.

Low-level expression of human Epidermal growth Factor Receptor-2 (HER2) in High-Grade Mullerian Tumors: Implications for therapy decision making.

Introduction: Reclassification of HER2-negative breast cancers to HER2 low-level expression allowed targeted anti-HER2 therapy in about 60% of patients, improving outcome. The high recurrence rates and often dismal outcomes with current therapies of high-grade Mullerian carcinomas, offers opportunity to explore anti-HER2 therapies in the gynecologic tract carcinomas. We investigated HER2 low expression as currently defined in breast carcinomas. Methods: We reviewed all high-grade Mullerian cancers between 2016 and 2021, where HER2 by IHC and/or FISH tests were available. Additional clinical information was recorded, and statistical analysis was performed using SPSS (version 27). Results: Forty (49.4%) tumors were endometrial, 20 (24.7%) ovarian, 16 (19.8%) fallopian tubal, and 5 (6.2%) primarily peritoneal. Overall, 17 (21.0%) were HER2 positive (IHC 3+/IHC 2+/FISH amplified), 31 (38.3%) HER2 low (IHC 1+/2+/FISH non-amplified), and 30 (37.0%) were HER2 negative (IHC = 0). HER2 low expression was noted in 15% ovarian, 25% fallopian tubal, 53% endometrial, and 60% peritoneal tumors; 34% and 21% of serous carcinomas, 63% and 13% of carcinosarcomas, and 67% and 33% of endometrioid carcinomas were HER2 low and HER2 positive respectively. HER2 negative and HER2 low expression had a significant association with primary tumor location (p = 0.001); endometrium and peritoneal tumors were more likely to be HER2 low and HER2 negative. During a mean follow-up of 13.2 months (range: 1-34), 5% of the patients were deceased. Conclusions: Based on the current HER2-low recommendations in the breast, about one-third of patients with high-grade Mullerian carcinomas might qualify for anti-HER2 therapy with a potential for improved progression-free and overall survival.

Benign Biphasic Tumors of the Mullerian Tract - a Mimic of Phyllodes Tumor. A Clinical-Pathologic Description of 21 Cases.

OBJECTIVE: A review of the clinical-pathologic characteristics and outcomes of biphasic polyps occurring in the female genital tract, not meeting the diagnostic criteria of Mullerian Adenosarcoma (MA). METHODS: An archival database search was run, after IRB approval, between 2001 and 2019, using terminology such as "Mullerian adenofibroma," "atypical Mullerian adenofibroma," "polypoid adenofibroma," and "atypical polyp with increased stromal cellularity." Two pathologists (JW and MRQ) reviewed all the retrieved cases and documented the morphologic features with particular emphasis on the presence of any features of Mullerian adenosarcoma. Follow-up data were also abstracted. RESULTS: Twenty-one cases, 12 cervical and 9 endometrial lesions, constituted the study cohort. Patients ranged from 26 to 64 years (median 49 years). On review, 20 of 21 of those cases showed Phyllodes-like architectural patterns. However, only one case showed all four features of MA, all of which were focal and inconspicuous. Follow-up (median duration of 5 years) did not document any recurrences in any of the 21 cases after excision. CONCLUSION: This series adds to the growing body of literature affirming the existence of benign biphasic Mullerian polyps encountered in the endometrium and cervix that fall short of the Mullerian adenosarcoma diagnosis.

Recurrent Primary Paget Disease of Vulva with Paget-Like Epithelial Cells in Papillary Dermis: Displaced or Invasion?

While histological diagnosis of Paget disease of vulva is mostly straightforward, identifying and confirming invasion can be challenging. Often invasion is accompanied by epidermal hyperplasia, marked inflammatory response and desmoplastic reaction. Diagnosis of invasion in Paget disease portends a poor outcome. We report findings from a recurrent primary vulvar Paget disease where overall histomorphology of possible invasive disease is unusual and raises a possibility of displacement of Paget cells in the dermis. We compare histology of the index case with known invasive vulvar Paget disease cases retrieved from our pathology archives. Unique histomorphology in the index case suggests a possibility of previous excision related dermal displacement of Paget cells.

Simultaneous p53 and KRAS mutation in a high-grade serous carcinoma with deceptive appearance of a low-grade carcinoma. A case report.

Low-grade and high-grade serous carcinomas have unique clinical, morphological, underlying molecular alterations, and vastly different biologic behavior (Prat et al., 2018, Vang et al., 2009). The differentiation into high and low-grade serous carcinoma is important for clinical management and prognosis and is easily recognized by practicing pathologists. High-grade serous carcinoma is characterized by marked nuclear atypia and pleomorphism, frequent, often atypical mitosis with papillary or three-dimensional clusters, p53 mutation, and block-like p16 staining. In contrast, low-grade serous carcinomas have a different morphologic appearance with micropapillary formation, small nests of tumor cells having low to intermediate grade nuclei, and absence of significant mitosis. Low-grade serous carcinoma is often associated with micropapillary variant of ovarian serous borderline tumor. The low-grade serous carcinoma shows wild type p53 expression, patchy p16 staining, and often K-RAS, N-RAS, and/or B-RAF mutation. Here we report a case of mullerian high grade serous with a deceptive morphology resembling low-grade serous carcinoma with micropapillary features and moderate nuclear atypia. However, the tumor is simultaneously p53 and K-RAS mutated. This case illustrates three critical issues; a) potential to be mistaken as a low-grade serous carcinoma because of morphologic appearance and relative uniform cytologic feature. b). raise the question of true progression of low-grade to high-grade serous carcinoma, a rare phenomenon as described in the literature, and c). whether the biologic behavior and/or response to therapy would differ from the classic forms.

Evaluation of Saccharomyces cerevisiae -like 1 (SEC14L1) in Gynecologic Malignancies Shows Overexpression in Endometrial Serous Carcinoma.

Saccharomyces cerevisiae -like 1 ( SEC14L1 ) is a member of the SEC14 family and is involved in liposoluble vitamin transfer, and in a large cohort of breast cancer cases, was one of the genes most significantly associated with lymphovascular invasion (LVI), and had a significant relationship with human epidermal growth factor receptor 2 status, survival, and histologic grade. In this study, 111 separate gynecologic tumors were studied for SEC14L1 protein expression, including: uterine adenosarcoma, ovarian clear cell carcinoma, endometrial stromal sarcoma, endometrioid carcinoma of the uterus, high-grade serous carcinoma, ovarian endometrioid carcinoma, uterine leiomyosarcoma, low-grade serous carcinoma, uterine carcinosarcoma, and uterine serous carcinoma (USC). Overall, LVI was noted in 31/111 (28%) cases, highest in uterine carcinosarcoma (5/11; 45%), high-grade serous carcinoma (9/21; 43%), and ovarian clear cell carcinoma (4/10; 40%). SEC14L1 was positive in 25/111 (23%) cases; the highest percentage and only statistically significant finding by tumor type was USC at 9/12 (75%) cases positive. No relation between LVI or survival and SEC14L1 expression was noted. The relation between USC, a tumor known to show human epidermal growth factor receptor 2 overexpression and SEC14L1 is a novel finding, the significance of which warrants further study.

A Snapshot of the Landscape of Endocervical Adenocarcinoma in Kenya: What Has HPV Got to Do with It?

OBJECTIVE: To determine the frequency of the HPV associated endocervical adenocarcinomas diagnosed at a tertiary referral laboratory in Kenya over a one-year period and classify them by histologic subtypes according to the proposed criteria by IECC. MATERIALS AND METHODS: This was a collaborative cross-sectional descriptive study. Formalin-fixed parrafin embedded tissue blocks of 29 confirmed cases of endocervical adenocarcinoma diagnosed at AKUHN between July 2017 and July 2018 were analyzed for presence of 14 hrHPV subtypes including types 16 and 18 using GenomeMETM's GeneNavTm HPV One qPCR kit. Variables analyzed included age, histologic subtype and presence or absence of hrHPV. RESULTS: Twenty-nine cases were analyzed (median age=48years, range 23-70 years), of which 27(93.1%) were positive for hrHPV, with type 16 alone positive in 11(40.7%) cases and present alone or in combination with others including type 18 in 21(72.4%) cases. All hrHPV positive cases had either type 16 or 18. Twenty cases (69.0%) were classified as usual type adenocarcinoma, all positive for hrHPV. Other HPV associated adenocarcinomas identified were mucinous, signet ring cell type (4), villoglandular (2) and mucinous, NOS (1). There were only two cases of non-HPV associated adenocarcinoma. CONCLUSION: In this series, we show that the proportion of HPV associated endocervical adenocarcinoma in Kenya is high and is particularly driven by types 16 and 18. Policy makers, hospitals and laboratories in East Africa should make an effort to avail the various techniques of detecting hrHPV critical in screening and diagnosis of endocervical adenocarcinoma.

Comparison of Cervical HSIL Outcome between Pregnant and Non-Pregnant Women.

OBJECTIVE: Variables predicting outcome of high-grade squamous intraepithelial lesion (HSIL) in pregnancy are unknown. The HSIL is usually managed conservatively during pregnancy. We aim to assess morphological features of HSIL diagnosed during pregnancy and identify variables predicting HSIL outcome in pregnant and non-pregnant women. METHODS: ThinPrep pap smears with HSIL in pregnant (2014-2019) and non-pregnant females (2017-2019) were identified. The pathology material from follow-up cervical samples was reviewed by two participating pathologists (TP and KS). Regression was defined as benign or residual low-grade squamous intraepithelial lesion. Histological findings were recorded and compared between pregnant and non-pregnant cohort. RESULTS: The HSIL regression rate was higher in colposcopic samples (16% vs. 0%; p=0.05) and follow up excisions (27% vs. 23%) from pregnant cohort. Overall regression rate was higher in pregnant versus non-pregnant cohort (34% vs. 23%; p=0.1). The stromal inflammation was prominent in biopsies from pregnant cohort (p=0.02). Presence of CIN 2 (versus CIN 3) in non-pregnant cohort predicted HSIL regression (p=0.04). The time to biopsy and excision (from pap smear) was significantly higher in pregnant cohort (p=0.0001). HSIL histological features (nuclear pleomorphism, hyperchromasia, nuclear contour irregularity, nuclear to cytoplasmic ratio, and mitosis) and HPV types were similar in both cohorts and did not predict regression. CONCLUSION: The higher rate of benign findings during HSIL follow up in pregnancy is likely related to duration and stromal inflammation. HSIL regression is frequently noted following CIN2 diagnosis in non-pregnant setting. HSIL histology is similar in postpartum and non-pregnant females.

Variants of in situ carcinoma of the endometrium: Clear cell and gastrointestinal types, with a review of the literature.

Two precursor lesions are commonly associated with endometrial carcinoma. Atypical endometrial hyperplasia/endometrial intraepithelial neoplasia is a known precursor lesion of endometrial endometrioid carcinoma, while endometrial intraepithelial carcinoma, is a recognized precursor lesion of endometrial high-grade serous carcinoma. Other than these two recognized entities, other rare precursor lesions for endometrial carcinoma do exist, although reported cases are relatively few and not universally recognized. This therefore poses diagnostic challenges in clinical practice. Here, we describe a series of rare precursor lesions of the endometrium identified at our institution, including clear cell and gastrointestinal variants, their morphologic and immunohistochemical characteristics, and review current literature regarding these variants. The information provided may guide the proper diagnosis and ultimately lead to effective clinical management in every-day practice.

Benign stratified intraepithelial mucinous proliferation of the uterine cervix: Significance of a previously unreported potential mimic of SMILE.

Stratified mucin-producing intraepithelial lesion (SMILE) is a histologic subtype of HPV-associated endocervical adenocarcinoma in situ. We have observed benign endocervical changes resembling SMILE. We aim to characterize this pattern and explore its potential association with dysplasia. We retrospectively retrieved all 296 consecutive cases accessioned as endocervical biopsies. Some included multiple specimens, totaling 483 biopsies and 219 endocervical curettages (ECC), n = 702. We included cases showing endocervical epithelial stratification often with pencillate (triangular-shaped) nuclei. We rejected cases in which layering represented tangential sectioning, metaplasia, microglandular hyperplasia, gastric type epithelial changes, and dysplasia. We found benign stratified intraepithelial mucinous proliferation in 51 patients, either with a multilayered (n = 27) or a two-layered appearance (n = 24). Overall, multilayered proliferation occurred in 6 % (29/483) of biopsies and in 0.9 % of ECCs (2/219). Two-layering was identified in 4 % of all biopsies (20/482) and was not seen in ECCs. Histologic findings included stratification, intracytoplasmic mucin, paler cytoplasm, low nuclear-to-cytoplasmic ratio, often pencillate nuclei, rare mitoses, and no apoptotic bodies. P16 immunohistochemistry (n = 12) was negative, suggesting absence of underlying high-risk HPV infection. HSIL was concomitant in 29.6 % (8/27) of patients with multilayered proliferation. Concurrent SMILE was not observed. We also reviewed 13 SMILE cases. Concurrent multilayered benign proliferation was identified in 54 % (7/13) of cases. We describe benign stratified intraepithelial mucinous proliferation of the cervix, which morphologically may overlap with SMILE. Its presence in most SMILE cases suggests a potential relationship. The multilayered form represents a diagnostic pitfall when mitotically active. Because of the often-coexistent HSIL, we propose that its presence should prompt scrutiny to rule out any associated dysplasia.

Somatic mutation analysis of Mesonephric-Like adenocarcinoma and associated putative precursor Lesions: Insight into pathogenesis and potential molecular treatment targets.

Aims: Mesonephric-like adenocarcinoma (MLA) is a recently described histologic tumor subtype of the Müllerian tract. MLA can arise in association with Müllerian lesions that share common mutations. We report three MLAs and hypothesize that concurrent endometriosis and cystadenofibroma with focal borderline changes might also carry common mutations. Methods and results: We searched "mesonephric" in our database from 2015 to mid-2021 to retrieve MLA cases. Somatic mutation analysis was performed on tumors and on associated benign proliferative lesions. All MLAs (2 ovarian and 1 uterine) harbored KRAS G12D or G12 V mutations. A PIK3CA alteration (H1047Q) was detected in one MLA and in the associated cystadenofibroma with focal borderline changes. The molecular profile of MLA-associated Müllerian lesions (endometriosis and seromucinous cystadenofibroma with focal borderline changes) was similar to concurrent adenocarcinoma. However, tumor contamination could not be excluded in the endometriotic lesion. Patients presented at various stages, with no evidence of post-operative recurrence after 15 months (FIGO IC) and 33 months (FIGO IIA2). One patient (FIGO IIIA1) died of disease 32 months after surgery. Conclusions: KRAS mutations commonly characterize MLA. At least some MLA-associated Müllerian lesions show MLA-like genetic profiles, suggesting a precursor role. As far as we are aware, we describe for the first time in MLA the potentially actionable H1047Q variant of PIK3CA.

Adenomatoid Tumor of Fallopian Tube With "Deciduoid" Morphology and Atypical Nuclear Features.

Adenomatoid tumor is a benign neoplasm of mesothelial origin. Adenomatoid tumor in female genital tract shows typical morphologic features with bland nuclei. Deciduoid morphology has not been reported in adenomatoid tumor. Tumors with deciduoid cells and atypical nuclear features may pose a diagnostic challenge and raise the suspicion of malignancy. We present a case of fallopian tube adenomatoid tumor with deciduoid morphology and atypical nuclear features in a 39-year-old woman with prolonged progestin therapy. We hypothesize that the unusual morphological changes in adenomatoid tumor, like deciduoid morphology and nuclear atypia, may be secondary to hormone effects.

Low-grade serous carcinoma with extensive osseous metaplasia arising from ovarian serous cystadenofibroma.

•Bilateral ovarian low-grade serous carcinoma presenting with extensive osseous metaplasia.•Both lesions arising directly from ovarian cystadenofibromas, skipping the "borderline phase".•No micropapillary serous borderline component was identified.•This case may represent a "skipped step" in low-grade serous carcinogenesis.

Epithelium Involving Bilateral Axillary Lymph Nodes: Metastasis, Misplaced, or Mullerian!

During breast cancer staging, histological evaluation of axillary sentinel lymph nodes (SLN) is usually straightforward. However, the exact characterization of a small epithelial deposit in an SLN can be challenging, especially during the frozen section examination. We report the first case of endosalpingiosis involving bilateral axillary lymph nodes. We review published literature on axillary endosalpingiosis and discuss the differential diagnosis of small epithelial deposits in an axillary SLN. Pathologists should consider benign epithelial rests and displaced epithelium as differential diagnoses for the microscopic epithelial nodal deposit, especially during the frozen section examination.