Fibroadenomas of anogenital mammary-like glands: from embryogenesis anomaly to apocrine origin.

Mammary-like anogenital fibroadenomas are rare entities within the wide spectrum of female genital pathology. Our paper provides an up-to-date review, by systematization of the concepts and controversies, from the origin to the development and the diagnosis of the lesion. The theories pertaining to its histogenesis incorporate its debated origin of ectopic mammary-derived lesions, of cutaneous apocrine, eccrine, sebaceous, and mammary-like anogenital glands. Although rare, both clinicians and pathologists should consider this lesion type within the differential diagnosis of anogenital pathology, regardless of the woman's age, and pathological confirmation is mandatory to exclude the possibility of other tumours, including malignancy. Immunohistochemistry may represent a useful tool in tumor characterisation and in differential diagnosis.