Objective: To describe a rare case of mammary type sclerosing adenosis arising in anogenital, mammary-like adnexal glands. Differential diagnosis is discussed and detailed review of literature is presented. Design: Two case reports. Setting: Private Biopsy Lab s.r.o. and Šikl‘s Department of Pathology, Charles University and Faculty Hospital, Pilsen. Methods: Included are two cases from Breast Registry, Biopsy Lab s.r.o. and from personal consulting registry of Prof. Michal, Šikl‘s Department of Pathology, Pilsen. Detailed morphology of the lesion is described and documented by pictures. The presence of myoepithelial cell is demonstrated by immunohistochemistry using streptavidin-bioptin detection system (LSAB+, Dako) and three conventional myoepithelial markers (actin S, calponin and CD10). Expression of estrogen and progesteron receptors and apocrine antigen GCDFP-15 were studied too. Results: There were two women at the age of 54 and 60-years with lesion located on vulva and anus; the maximum tumor diameter was 7 and 10 mm, respectively. The histological picture was virtually the same in both cases displaying under hyperplastic epidermis small glands proliferation set in sclerotic fi brous stroma. In spite of relatively sharp circumscription, the chaotic and irregular distribution of the glands imparted the invasive image of the lesion. The luminal cells showed no cytological and nuclear atypia and visible was only minimal regular mitotic activity. The signs of luminal, decapitation-type, apocrine secretion were dispersal seen throughout the lesion. By immunohistochemistry the myoepithelial cells regularly and systematically decorated periphery of the glands and all the composition was similar to sclerosing adenosis in the breast including massive hormonal receptors expression. In the periphery of one lesion an insolated, single, typical anogenital gland was found. Features of conventional papillary hidradenoma were not seen. Conclusion: Mammary – type anogenital adnexal glands are regularly present in vulvar and perianal skin; these are considered there as a substrate for analogous lesion occurring in the breast (lactation change, papilloma and fi broadenoma, but also some types of carcinomas including primary extrammary Paget‘s disease). In these physiological structures there are combined features of both eccrine and apocrine adnexal glands creating a primitive caricature of basic tubulolobular unit in the breast. Their existence dispel historical dogma about running of the embryonal milk lines or mammary ridges and explains the fi ndings of varied scale of neoplasms differing from well known lesion derived from conventional adnexal glands.

        Key words: anogenital adnexal glands, mammary-like (mammary-type) sweat glands, vulva, anus, sclerosing adenosis