Hidradenoma papilliferum with mixed histopathologic features of syringocystadenoma papilliferum and anogenital mammary-like glands: report of a case and review of the literature.

Hidradenoma papilliferum of the anogenital region was previously believed to originate from apocrine glands but has recently been accepted as originating from anogenital mammary-like glands. We describe a case of hidradenoma papilliferum with mixed features of syringocystadenoma papilliferum and mammary-like glands from the left labia majora of a 25-year-old woman. Histopathologically, the lesion showed an epithelial lining with apocrine secretion, and like syringocystadenoma papilliferum, the lesion extended from the epithelium as invaginations into the dermis. Adjacent to this lesion were ductal and glandular structures resembling normal mammary tissue. This review of the literature highlights the heterogeneity and complexity of lesions arising from anogenital mammary-like glands, and this case serves as further documentation of the association between anogenital mammary-like glands and hidradenoma papilliferum.