Adenomyoepithelioma of the breast: fine-needle aspiration biopsy and histologic findings.

Adenomyoepithelioma is an uncommon tumor of the breast which clinically presents as a discrete nodule and histologically is composed of lumenal spaces lined by a mixture of epithelial and myoepithelial cells. It has a spectrum of histologic appearances which are gradually gaining wider recognition. There are, however, only a few descriptions of the fine-needle aspiration biopsy (FNAB) findings in adenomyoepithelioma. We report the FNAB and histologic features of a mammary adenomyoepithelioma which contained a prominent epithelial component including a focus of marked epithelial atypia. This expands the spectrum of FNAB findings which have been reported in adenomyoepithelioma.