Six cases of invasive breast carcinoma with unusual morphological features are reported. The ages of the female patients ranged from 46 to 79 years (mean 60.5). All tumours had areas typical of an adenomyoepithelioma. In three cases adenomyoepithelioma gradually merged with low-grade adenosquamous carcinoma. In the other three patients a sarcomatoid carcinoma was associated with adenomyoepithelial areas. A common origin is proposed for these neoplasms, which extends the morphological spectrum of epi-myoepithelial cell tumours.