Atypical apocrine proliferation involving anogenital mammary-like glands of the perianal region.

Anogenital mammary-like glands (MLGs) are a normal constituent of the anogenital area showing similarities to breast glands. MLGs are recognized to be the possible origin for various neoplastic and reactive conditions that show homology to their mammary counterparts. We report the case of an 85-year-old woman presenting with 10 cm polypoid mass of the perianal region. Histopathological examination of the excised lesion showed atypical apocrine proliferation arising in a complex lesion with features of fibroadenoma, adenosis and hyperplastic and cystic change. Normal MLGs were observed at the tumor periphery. There was no recurrence after 3 years of follow up. This report represents an illustration of the complexity of lesions developed from MLG.