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11 May 2012 - Case of the Week #241
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Thanks to Dr. Saroona Haroon, The Aga Khan University Hospital (Pakistan), for contributing this case. This case was reviewed in May 2020 by Dr. Jennifer Bennett, University of Chicago and Dr. Carlos Parra-Herran, University of Toronto.
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Case of the Week #241
A 30 year old Asian woman presented with painless vulval swelling for the past 7 months. Clinically, it was diagnosed as a Bartholins cyst. At excision, the swelling was 2 cm, circumscribed and firm.
What is your diagnosis?
Left to right: CD34, desmin, smooth muscle actin, vimentin
Angiomyofibroblastoma is a rare, benign, mesenchymal vulvar tumor, first described in 1992 (Am J Surg Pathol 1992;16:373). It occurs almost exclusively in the vulvovaginal region of women or the inguinoscrotal region of men
Grossly, it is well circumscribed, usually < 5 cm. Histologically, there are alternating hypercellular and hypocellular areas composed of spindle cells and plump stroma cells, often in clusters, with eosinophilic cytoplasm that aggregate around small, capillary-like blood vessels. Mast cells are common. There may be binucleated or multinucleated cells. There is minimal stromal mucin, rare/no red blood cell extravasation, no atypia and rare/no mitotic figures.
Angiomyofibroblastoma is immunoreactive for vimentin, desmin, ER and PR, and usually negative for keratin, S100 and actin (Mod Pathol 1996;9:284).
The differential diagnosis includes aggressive angiomyxoma. However, angiomyofibroblastoma has circumscribed borders, higher cellularity, more blood vessels (which lack prominent hyalinization), frequent plump stromal cells, minimal stromal mucin, and only rare erythrocyte extravasation.
Cellular angiofibroma, also in the differential diagnosis, is uniformly moderately cellular, with hyalinized vessels and bland spindle cells, but usually no plump epithelioid cells (Stanford School of Medicine).
Angiomyofibroblastoma has benign behavior, and does not recur after excision.
Nat Pernick, M.D., President
and Liz Parker, B.A., Associate Medical Editor
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