Carcinoma in a breast fibroadenoma.

A 48-year-old woman presented with a long history of a lump in the breast, which was clinically diagnosed as a fibroadenoma. Cytologic examination of fluid aspirated intraoperatively demonstrated groups of carcinoma cells. Excision of the mass showed that this discrepancy was due to carcinoma within a fibro adenoma. Reports of such an occurrence are few, and none, to the best of our knowledge, has previously documented the cytologic findings.