RESUMEN
Diagnosing accessory breast tissue in a male patient is difficult when the condition is unilateral, and there is no areola or nipple. Pseudoangiomatous hyperplasia of the mammary stroma is an uncommon benign mesenchymal proliferation that may mimic low-grade angiosarcoma. We report herein an example of tumoriform pseudoangiomatous hyperplasia of the stroma arising in the accessory breast tissue of a 38-year-old man. The condition presented as a palpable tender axillary mass. Histopathologically, there were no changes of gynecomastia. Only two cases of pseudoangiomatous hyperplasia of the stroma have been previously reported in the accessory breast tissue of men showing unilateral or bilateral gynecomastia. Our case is the first report without associated gynecomastia. Radiologic imaging features are not sufficiently specific to enable a prospective diagnosis of pseudoangiomatous hyperplasia of the stroma. Microscopic examination of the lesion is indispensable in making a definitive diagnosis. Awareness of the condition can avoid difficulty in diagnosing it. Aberrant breast tissue with mass-forming pseudoangiomatous hyperplasia of the stroma, whilst rare, should be included among the benign proliferative mesenchymal lesions of the axilla. Keywords: aberrant breast tissue-accessory breast tissue-pseudoangiomatous stromal hyperplasia-gynecomastia-angiosarcoma-axilla.