Adenomyoepithelioma of the breast--its diagnostic problems and histogenesis.

We report three cases of adenomyoepithelioma of the breast that occurred in middle aged women. The tumor is characterized by a balanced proliferation of epithelial tubules and surrounding myoepithelial cells that are spindle shaped or have clear cytoplasms. The first case mimicked tubular adenoma in the initial biopsy. However, on excision it turned out to be an adenomyoepithelioma of the tubular. The other two cases were lobulated types and had fibroadenomatous areas. The morphologic appearance of this tumor varies, making it misleading to other benign or even malignant lesions. The tumor has a potential for local recurrence, therefore, wide excision is recommended for proper diagnosis and treatment.