Adenomyoepithelioma of the breast. A case report.

Adenomyoepithelioma is a proliferative disorder of both epithelial and myoepithelial cells. This lesion may be found in salivary glands, skin appendages and, very rarely, in the mammary gland. Adenomyoepithelioma was first described in 1970 and very few cases have so far been reviewed in the literature. This paper reports the clinical, histological and immunohistochemical characteristics of an adenomyoepithelioma in a 24 year old woman; to our knowledge this is the first published case in such a young patient. The clinical feature suggested a fibroadenoma. A more complete study of the excised tumor tissue by immunohistochemical and ultrastructural analysis proved that the correct diagnosis was adenomyoepithelioma. Whether adenomyoepithelioma is a benign or a low-grade malignant lesion is still controversial and, therefore, the therapeutic approach is not well defined.