Breast tissue in benign tumor of anal margin

espanolResumen: Introduccion: Los adenomas en la region anogenital son infrecuentes y el origen de este tipo de lesion ha creado confu- sion. En el pasado estas lesiones se han considerado como tejidos ectopicos mamarios o como glandulas apocrina cutanea. Mas recientemente han sido definidas como glandulas anogenital de tipo mamario. Presentacion del caso: Este caso presenta una masa anogenital de origen ectopico en una mujer de 47 anos de edad. Las secciones de tejido microscopico mostraron un patron morfologico similar al de un fibroadenomas mamario, y la inmuno- tincion demostro la presencia de receptores de estrogenos y receptores de progesterona. El diagnostico definitivo fue un adenoma apocrino tubulo-papilar sin signos de malignidad. Conclusion: Cuando se encuentra un tumor del margen anal de origen desconocido, es oportuno considerar, aunque muy raros, los adenomas que imitan los tejidos mamarios. EnglishAbstract: Background: Adenomas in the anogenital region are uncommon and the origin of this kind of lesion has created confusion. In the past these lesions have been considered as ectopic breast tissues or as cutaneous apocrine glands. More recently they have been defined as mammary-type anogenital glands. Methods: This case reports an anogenital mass in a 47-year-old woman that was removed and subsequently studied through a pathological and immunostaining study. Results: Microscopic tissue sections showed a morphologic pattern similar to that of a mammary fibroadenomas, and immunostaining demonstrated the presence of oestrogen receptors and progesterone receptors. The definitive diagnosis was an apocrine adenoma tubulo-papillary without signs of malignancy. Conclusion: When a tumour of the anal margin of unknown origin is found, it is opportune to consider, although very rare, the adenomas that mimic the mammary tissues