BREAST-CARCINOMA IN A FIBROADENOMA - DIAGNOSIS BY FINE-NEEDLE ASPIRATION CYTOLOGY

We describe a case of ductal carcinoma in situ (DCIS) occurring in a f ibroadenoma diagnosed by fine needle aspiration (FNA) cytology. The cy tological features comprised a small population of pleomorphic cells a dmired with a dominant population of bland epithelial cells showing fe atures consistent with those of a fibroadenoma. Excision biopsy confir med the presence of DCIS within an otherwise typical fibroadenoma. Rec ent reviews have emphasised the potential for fibroadenoma to cytologi cally mimic carcinoma, leading to false positive findings, however the converse is also possible. We conclude that a false negative cytologi cal diagnosis may be avoided by recommending histological confirmation by excision biopsy when significant atypia is present, even if the ov erall pattern is that of a fibroadenoma.