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5 December 2013 - Case of the Week #293
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Thanks to Dr. Anna Liava (Greece) and Dr. Vasiliki Tzelepi, University of Patras (Greece), for contributing this case and discussion. This case was reviewed in May 2020 by Dr. Jennifer Bennett, University of Chicago and Dr. Carlos Parra-Herran, University of Toronto. To contribute a Case of the Week, follow the guidelines on our Case of the Week page.
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Case of the Week #293
A 60 year old woman presented with a slow growing, 2 cm nodule in the left labium majus of the vulva, present for one year, which was biopsied. Clinical and radiologic examination of the breasts revealed no significant findings.
What is your diagnosis?
Adenocarcinoma of the vulva with apocrine features (mammary-type versus sweat gland origin)
The tumor consists of irregular glands composed of large polygonal cells with abundant eosinophilic cytoplasm, large hyperchromatic nuclei and prominent nucleoli. Atypical mitotic figures are noted. The tumor cells have a high Ki67 index (see above), but the cells were negative for GCDFP-15 (not shown). ER and PR were not performed.
Cutaneous vulvar carcinomas are usually squamous cell carcinomas. Primary vulvar adenocarcinomas are rare, with a poorly understood histogenesis. They are classified into a) mammary-type adenocarcinomas, b) bartholin gland carcinomas, c) extra-mammary Paget disease, (d) carcinomas of sweat gland origin, (e) intestinal-type adenocarcinomas and (f) HPV-related adenocarcinomas (Pathol Res Pract 2009;205:131), WHO classification of Tumours of Female Genital Organs).
Mammary-like adenocarcinoma may originate from anogenital ER+, PR+ mammary like glands in the interlabial sulci, and is often accompanied by these native glands. Extra-mammary Paget disease has large pale staining tumor cells, usually in the lower epidermis, in nests, glandular spaces or continuously along the basement membrane. The disease is confined to the epithelial compartment, however invasion into the stroma may occur (invasive Pagets disease). Pure and invasive forms of Paget’s disease in the vulva can arise from the vulvovaginal epithelium or be secondary from urothelial carcinoma or anorectal carcinoma. Thus, in the setting of Pagets disease of the vulva these possibilities need to be excluded. Extramammary Pagets disease arising from vulva has a mammary-type immunophenotype, including frequent expression of GATA3, GCDFP15, mammaglobin, hormone receptors and Her2Neu. Sweat gland carcinoma derives from native apocrine sweat glands, is usually ER-, PR-, and composed of glandular or papillary cords and tubules, with variable pagetoid components. Intestinal-type carcinomas, also known as cloacogenic adenocarcinoma, display intestinal differentiation; this diagnosis is rare and one of exclusion (metastases from colorectal carcinoma should be first excluded). HPV-related adenocarcinomas of the vulvovaginal and anal region have been recently described; they show morphology akin to HPV-related (usual) endocervical adenocarcinomas (Mod Pathol 2020;33:944).
In this case, although ER and PR staining was not done, the absence of GCDFP-15 staining, and the lack of mammary-like glands near the tumor, suggests a sweat gland origin (Am J Dermatopathol 2012;34:773).
Due to its rarity, the prognosis is not well characterized, although regional nodal metastases and distal metastases have been reported.
Nat Pernick, M.D., President
and Palak Thakore, Associate Medical Editor
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