International Journal of Gynecological Pathology最新文献

{"title":"HER2 Status in Low-grade Serous Ovarian Tumors.","authors":"Kristýna Němejcová, Adam Šafanda, Michaela Kendall Bártů, Nikola Hájková, Jana Drozenová, Pavel Fabian, Jan Laco, Radoslav Matěj, Gábor Méhes, Petr Škapa, Ivana Stružinská, Pavel Dundr","doi":"10.1097/PGP.0000000000001059","DOIUrl":"10.1097/PGP.0000000000001059","url":null,"abstract":"<p><p>Using immunohistochemistry, we examined a large cohort of 135 ovarian tumors, made up of 96 low-grade serous carcinomas (LGSCs) and 39 serous borderline tumors (micropapillary variant, mSBT), with the aim of exploring their HER2 status (overexpression). We followed with comprehensive genomic analyses on this sample set from our previous study, which revealed HER2 mutation in 5% (4/75) of LGSC and 10% (3/29) of mSBT. No cases were evaluated as HER2-positive, but 6 LGSCs and 1 mSBT were scored as HER2 1+, and 2 LGSCs and 1 mSBT showed the so-called HER2 \"ultra-low\" phenotype. This could be of clinical value as a potential therapeutical target concerning emerging therapeutic treatments (antibody conjugates). However, the clinical significance of this expression still needs to be established.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"331-335"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142125670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Spectrum of Vascular Lesions of the Upper Female Genital Tract: A Report of 55 Cases.","authors":"Ting Zhao, Yin P Hung, Kyle M Devins, Robert H Young, Esther Oliva","doi":"10.1097/PGP.0000000000001109","DOIUrl":"10.1097/PGP.0000000000001109","url":null,"abstract":"<p><p>Upper female genital tract vascular proliferations are rare and generally not well characterized. We evaluated types, differences in distribution, and associations of such lesions. Fifty-five vascular lesions were identified: 42 benign (ovary 24; uterine corpus 11; para-adnexal 4; fallopian tube 1; ovaries, fallopian tubes, and corpus 1; ovary and fallopian tube 1) and 13 angiosarcomas. Patients with benign vascular lesions had a mean age of 55 (range: 13-82) yr. Twenty-six lesions were incidental findings, and 11 were associated with clinical manifestations. They had a mean size of 2.0 (range: <1-13) cm, and often were grossly cystic and hemorrhagic. Uterine benign vascular lesions included 6 arteriovenous malformations, 3 venous hemangiomas/malformations, 2 cavernous hemangiomas, and 1 mixed venous-cavernous hemangioma. In the ovary, there were 10 anastomosing hemangiomas, 8 arteriovenous malformations, 6 venous (2 in mature cystic teratomas, 1 bilateral in a patient with Klippel-Trenaunay syndrome), and 2 cavernous hemangiomas. Anastomosing hemangiomas were frequently associated with peripheral stromal luteinization/hilar cell hyperplasia; intravascular growth, extramedullary hematopoiesis, and one with adipocytic metaplasia. Venous hemangiomas/malformations were noted at a younger age in the ovary when compared to the uterine corpus. Patients with angiosarcomas had a mean age of 32 (range: 12-58) yr and a mean tumor size of 9.7 (range: 1.5-23) cm. Eight presented with a pelvic mass. Most angiosarcomas were grossly hemorrhagic and/or necrotic. Eleven arose in the ovary, 4 of them were associated with mature cystic teratoma, 1 with adenosarcoma with sarcomatous overgrowth, and 1 was part of a malignant mesenchymoma. Five were predominantly spindled, 3 epithelioid, 2 spindled and epithelioid, and one pleomorphic. Both uterine angiosarcomas were epithelioid. Follow-up was available for 8 patients: 7 died of disease between 6 and 43 mo, and 1 was alive and well at 106 mo. Vascular lesions in the upper female genital tract are uncommon, morphologically heterogeneous, and more frequent and clinically evident in the adnexa. Anastomosing hemangioma is the most common benign vascular lesion in the ovary and may be misdiagnosed as a steroid cell tumor due to associated stromal luteinization/hilar cell hyperplasia. Arteriovenous malformation is the most common benign vascular lesion in the uterine corpus. Angiosarcomas may be associated with another neoplasm, more commonly mature cystic teratoma, and have a poor prognosis.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"291-307"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular and Clinicopathologic Characterization of HER2-overexpressed Squamous Cell Carcinoma of the Cervix.","authors":"Rachelle P Mendoza, Madhurya Ramineni, Kristina Doytcheva, Elmer C Gabutan, Raavi Gupta, Cole Miller, Donghyuk Choi, Anusha Vemuri, Renee Briese, Lisa Brannon, Anum Shahid, Kristin Petras, Minhaz Ud Dean, Carrie Fitzpatrick, Jeremy Segal, Peng Wang, Ricardo R Lastra","doi":"10.1097/PGP.0000000000001068","DOIUrl":"10.1097/PGP.0000000000001068","url":null,"abstract":"<p><p>HER2 amplification in cervical cancer has been associated with worse clinical prognosis and a potential favorable response to HER2 inhibitors. Immunohistochemistry for the HER2 receptor is a universally accepted surrogate test for HER2 amplification, but no standardized scoring system currently exists for cervical carcinomas. In this study, we investigated HER2 overexpression in cervical squamous cell carcinoma and correlated it with HER2 amplification using fluorescence in situ hybridization (FISH) and molecular methods. Seventy-two cases of human papillomavirus-associated cervical cancer were retrospectively reviewed, and at least 2 representative tumor sections were stained for HER2. HER2 scoring was performed using the 2018 American Society of Clinical Oncology/College of American Pathologist breast cancer criteria, and cases with equivocal (2+) to positive (3+) expression were analyzed for HER2 amplification using FISH and next-generation sequencing. The average patient age was 50 yrs (range: 27-85 yr), with most patients being African American (73.6%) and diagnosed at FIGO stage I (65.3%). Nineteen (26.4%) had equivocal HER2 expression and 4 (5.5%) showed positive expression. Three of the 4 cases with positive expression had enough tumors for FISH, and all 3 were amplified. Three cases with equivocal expression showed HER2 polysomy on FISH, and none showed HER2 amplification. Late clinical stage, high tumor grade, and regional lymph node metastasis were significantly correlated with HER2 overexpression and HER2 amplification. Next-generation sequencing of the 3 HER2-amplified tumors showed amplification of various genes, including CD274, JAK2, BIRC3, and ERBB2, and a PIK3CA missense mutation. In summary, HER2 immunohistochemistry is a reliable predictive marker of HER2 amplification in cervical cancer.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"323-330"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lamin A and Emerin Protein Expression Remains Consistently Low and Nuclear Size is Unchanged in Normal Endometrium, Precancerous Lesions, and Endometrioid Carcinoma.","authors":"Yoshimi Nishijima, Naoki Inoue, Akira Iwase, Hayato Ikota, Sayaka Kobayashi, Hideaki Yokoo, Masanao Saio","doi":"10.1097/PGP.0000000000001080","DOIUrl":"10.1097/PGP.0000000000001080","url":null,"abstract":"<p><p>Nuclear laminar or inner nuclear membrane proteins, including lamin A, B1, and B2 and emerin, are involved in maintaining nuclear morphology. However, their expression patterns vary among tumors and remain incompletely understood. Endometrioid carcinoma (EC) exhibits mild nuclear atypia, although the underlying reasons have not been thoroughly explored. In this study, we quantitatively analyzed emerin and lamin A, B1, and B2 expression levels in normal endometrium (NE), precancerous lesions, and EC using computer-assisted image analysis to assess the proteins' roles in nuclear morphologic change during tumorigenesis. From NE to EC, nuclear size remained unchanged, and lamin A and emerin were consistently expressed at low levels, whereas lamin B1 and B2 expression gradually decreased. Given the association between lamin A and emerin as well as their roles in nuclear morphology, these results indicate that their consistent low expression may underlie the preservation of nuclear size and shape in EC relative to NE. Conversely, lamin B1 and B2 are implicated in tumor progression rather than nuclear morphology maintenance. As lamin A and emerin are expressed in many organs and tumors, the consistently low expression of these proteins from NE to EC highlights a notable feature of the endometrium and endometrial carcinogenesis.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"340-348"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic Utility of Deeper Level Tissue Sections of Negative Peritoneal Biopsies for Clinically Suspected Endometriosis.","authors":"Constance V Chen, Megan S Orlando, Mary Kathryn Abel, Jessica Opoku-Anane, Joseph T Rabban","doi":"10.1097/PGP.0000000000001071","DOIUrl":"10.1097/PGP.0000000000001071","url":null,"abstract":"<p><p>Definitive diagnosis of endometriosis is established by histologic confirmation in tissue from surgically visualized lesions; however, the diagnostic sensitivity of this approach varies widely. We hypothesized that incomplete tissue block sampling may contribute to false-negative diagnosis, particularly if the focus of endometriosis in the tissue section is scant. This study defined the diagnostic value of deeper level tissue sections in cases in which none of the specimen parts contained endometriosis on the initial tissue sections, using the World Health Organization essential criteria for diagnosis of endometriosis (presence of endometrial glands and endometrial stroma). Among 135 patients who underwent surgery for suspected endometriosis by a single surgeon at an academic institution from 2015 to 2019, the initial tissue sections resulted in a diagnosis of endometriosis in 73.3% (99/135), at an average diagnostic yield of 5.9 slides per diagnosis of endometriosis. An additional 9 patients were diagnosed with endometriosis by deeper level tissue sections, increasing the diagnostic rate to 80% (108/135). This 6.7% gain in the diagnostic rate came at an increase in resource utilization, with an overall overage diagnostic yield of 9.8 slides per diagnosis of endometriosis. Overall, 8.3% of patients had a false-negative diagnosis on the initial tissue sections. When extrapolated to a population level, the number of patients potentially affected by this source of false-negative diagnosis and the implications for patients merit consideration of the use of deeper level sections if none of the initial sections of any of the specimens contains endometriosis.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"349-354"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vulvar Cellular Angiofibroma With Cytologic Atypia and Sarcomatous Transformation: A Clinicopathologic Analysis.","authors":"Anna S Erem, Krisztina Hanley, Gulisa Turashvili","doi":"10.1097/PGP.0000000000001041","DOIUrl":"10.1097/PGP.0000000000001041","url":null,"abstract":"<p><p>Cellular angiofibromas (CAFs) are benign mesenchymal neoplasms of the vulva and lower genitourinary tract. Although most cases are benign with excellent prognosis, data on CAFs with cytologic atypia (aCAF) and sarcomatous transformation (tCAF) is limited. We identified 13 vulvar CAFs comprising 4 aCAFs and 9 tCAFs. The median age at presentation was 49  yr (40-84). All tumors involved the subcutis with a median size of 4.75 cm (0.8-11.7). Vascular and stromal hyalinization was present in all cases. Fascicular growth pattern and chronic perivascular inflammation were seen in 10 cases, followed by wispy collagen in 11 and stromal inflammation in 12. Common features were fat entrapment (n=8), stromal edema (n=7), and hemangiopericytoma-like vessels (n=5), while myxoid change, necrosis (n=3 each), hemorrhage, collagen bundles (n=2 each), solitary fibrous tumor-like appearance, and large hyalinized vessels (n=1 each) were rare. The atypia ranged from isolated atypical cells to foci of multinucleated cells, with brisk mitoses in 1 case. The sarcomatous transformation involved 10% to 80% of total tumor volume and comprised features of well-differentiated liposarcoma, pleomorphic liposarcoma, leiomyosarcoma, and spindle and epithelioid cell sarcoma. Diffuse p16 expression was present in 2 tCAFs. Of 10 patients with available follow-up (median: 103.3 mo, 13.3-156.6), 2 (20%) recurred at 41 mo and 66 mo and remained disease-free at 157 and 99  mo post reexcision, respectively. The study provides a detailed clinicopathologic characterization of rare variants of CAF, aCAFs, and tCAFs, and reports rare recurrences, most likely due to incomplete surgical excision.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":"314-322"},"PeriodicalIF":1.6,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143614892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinicopathological and Molecular Characterization of High Grade Endometrial Carcinomas of No Specific Molecular Profile (NSMP) Stratified by ER Status.","authors":"Patrick Thaddeus Timmermans, Alicia Leon-Castillo, Claire Kramer, Natalja Ter Haar, Vincentius Smit, Marie Boennelycke, Estrid Hogdall, Claus Hogdall, Carien L Creutzberg, Nanda Horeweg, Gitte Ortoft, Tjalling Bosse","doi":"10.1097/PGP.0000000000001112","DOIUrl":"https://doi.org/10.1097/PGP.0000000000001112","url":null,"abstract":"<p><p>This study represents a omprehensive characterization of high-grade endometrial carcinoma (EC) of no specific molecular profile (NSMP) to improve our understanding of their poor clinical outcome. A previously molecularly classified cohort of 412 high-grade EC from the Danish Cancer Registry was extensively reviewed by 2 expert pathologists blinded for associated clinical and molecular data. Immunohistochemistry (IHC) was performed to determine ER, PR, and L1CAM status and a 10% cut-off value was applied for positivity. Shallow whole-genomic sequencing (sWGS) and next-generation sequencing (NGS) was performed to describe the molecular landscape. Survival analysis was performed using the Kaplan-Meier method, and survival difference was tested using the log-rank test. Of the 57 high-grade NSMP tumors, ER negativity was found in 30 (53%). All clear cell NSMP EC (n=12, 21%) were ER negative. L1CAM overexpression was found in 29 high-grade NSMP EC (53%) and showed overlap (n=20, 69%) with ER negativity. A high frequency of copy number (CN) events and fraction genome altered (FGA) was observed, with the median number of CN events clustering by ER status (28 vs. 43, P<0.05). Overall, the cohort showed a 52% (CI: 31.6%, 72.4%) 5-yr overall survival (OS) and 61% (CI: 42.6%, 79.4%) 5-yr disease-specific survival (DSS). No significant additional prognostic refinement was found when stratifying for ER status (5-yr OS: 46% vs. 65%, P=0.068). High-grade NSMP ECs are a heterogenous group of tumors with high prevalence of loss of ER, L1CAM overexpression, and substantial copy number alterations. Within this group, no prognostic effect of ER was identified, providing support for grouping these tumors into one risk group. This work adds to the growing body of evidence that both high-grade and/or loss of ER expression can be used to identify NSMP EC patients with a poor clinical outcome.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144158499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bilateral Borderline Serous Tumor of Fallopian Tube in a Child With Klippel-Trenaunay Syndrome: An Exceptionally Rare Combination.","authors":"Neha Bakshi, Sonia Badwal, Satish Kr Aggarwal, Shashi Dhawan","doi":"10.1097/PGP.0000000000001100","DOIUrl":"https://doi.org/10.1097/PGP.0000000000001100","url":null,"abstract":"<p><p>Klippel-Trenaunay syndrome (KTS) is a rare overgrowth disorder characterized by capillary malformations, vascular anomalies, and limb length discrepancies. It is a congenital, mostly sporadic disorder with unknown pathogenesis, though recent studies have shown an association with somatic mosaic-activating mutations in the PIK3CA gene. The prognosis is variable, depending on the clinical presentation. Visceral involvement in KTS is rare, usually in the form of hemangiomas or venous malformations. Varied neoplastic pathologies have been reported in KTS; however, unlike other overgrowth syndromes, no clear association between KTS and malignancy has so far been elucidated. We report herein an account of a 2-yr-old female child with KTS who presented with abdominal distention and was diagnosed to have a serous borderline tumor (SBT) of bilateral fallopian tubes. Fallopian tube SBT is exceptionally rare and, to the best of our knowledge, has only been reported once previously in a premenarchal patient, who, incidentally, also had KTS. Bilateral fallopian tube involvement in a pediatric SBT has not been described hitherto.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144600344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Case Report of Uterine Dedifferentiated Mesonephric-Like Adenocarcinoma With Comprehensive Molecular Profiling.","authors":"Elaina Daniels, David B Chapel, Douglas A Rottmann, Stephanie L Skala, Jean H Siedel, Tao Huang","doi":"10.1097/PGP.0000000000001117","DOIUrl":"https://doi.org/10.1097/PGP.0000000000001117","url":null,"abstract":"<p><p>Mesonephric-like adenocarcinoma (MLA) of the uterus is a rare, aggressive malignancy of presumed Müllerian origin that was recently included in the 2020 World Health Organization (WHO) Classification of Female Genital Tumours. MLA is challenging to diagnose given its rarity and morphologic heterogeneity. The recently published first case report of MLA that underwent dedifferentiation via TP53 mutation expands the morphologic spectrum of dedifferentiated carcinoma. In here, we describe a second case of an endometrial MLA with dedifferentiation from a 41-yr-old woman who presented with bilateral ovarian masses, peritoneal carcinomatosis, and hypercalcemia. A diagnosis of small cell carcinoma of the ovary, hypercalcemic type, was initially rendered at an outside institution from an omental biopsy, which only showed the undifferentiated component. The subsequent endometrial curettings performed at our institution showed both the MLA and undifferentiated components, each of which demonstrated distinct immunophenotype with the immunoreactivity to epithelial markers, GATA3 and TTF1 limited to the MLA component and the aberrant nuclear expression of beta catenin, global loss of expression of SMARCA4 and loss of expression of SMARCA2 limited to the undifferentiated component. Molecular studies on the undifferentiated component from the omental biopsy identified not only a mutation in KRAS, gene mutation commonly seen in MLA, but also mutations in SMARCA4 and CTNNB1. In summary, we describe a second case of dedifferentiated MLA with dedifferentiation driven by various genetic alterations, including SMARCA4 and CTNNB1 gene mutations, novel gene alterations that have never been described in dedifferentiated MLA.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microcystic Adnexal Carcinoma (MAC) and Eccrine Cutaneous Mixed Tumor (ECMT): 2 Cases of Rare HPV-independent Vulvar Cutaneous Adnexal Tumors.","authors":"Margarita Consing Gangelhoff, Josephine Harter, Virginia Kurth, Paul Weisman, Jin Xu","doi":"10.1097/PGP.0000000000001116","DOIUrl":"https://doi.org/10.1097/PGP.0000000000001116","url":null,"abstract":"<p><p>Microcystic adnexal carcinoma (MAC) and eccrine cutaneous mixed tumor (ECMT) are both cutaneous adnexal tumors that may occur in the vulvar region, but are very rare at this site. Consequently, they may not enter the differential diagnosis of vulvar lesions for gynecologic pathologists in a subspecialized practice setting. Here we report a case of MAC and a case of ECMT recently diagnosed at our institution and underscore key histologic and immunophenotypic features of each lesion that can assist in their correct identification. Both MAC and ECMT have a tubular to corded pattern of lesional cells within a desmoplastic to chondromyxoid stroma. However, MAC shows true eccrine sweat duct differentiation, characterized by 2 SOX10 negative cell layers, including an outer p63+/p40+/EMA- basal cell layer and an inner p63-/p40-/EMA+ ductal layer. The main differential diagnostic considerations for vulvar MAC include other cutaneous adnexal tumors with true eccrine sweat duct differentiation, namely syringoma and squamoid eccrine ductal carcinoma (SEDC). Conversely, ECMT is characterized by a single SOX10+ cell population without immunoreactivity for p63 or p40. The main differential diagnostic considerations for ECMT include the apocrine variant of cutaneous mixed tumor (ACMT)-the cutaneous analog of salivary gland pleomorphic adenoma-and other SOX10+ salivary gland-type neoplasms. Unlike the recently described vulvar analog of HPV-associated multiphenotypic sinonasal carcinoma, neither MAC nor ECMT are HPV-associated and both are therefore p16 negative. In summary, we report one case each of vulvar MAC and ECMT and discuss the key histologic features and ancillary testing results that can help to differentiate these lesions from their morphologic mimics.</p>","PeriodicalId":14001,"journal":{"name":"International Journal of Gynecological Pathology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144077931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}