Fibroadenoma is a common benign breast tumor that has a rare malignancy rate. However, various studies reported that it is associated with a certain increase in breast cancers.

We report three cases of malignancy arising from a breast fibroadenoma. They were 32, 36 and 52 years old and presented with a lump of recent onset. Anyone of mammography, ultrasonography and cytologic examination could diagnose malignancy exactly. But cytological examination demonstrated atypical cells with fibroadenoma in two cases. Wide excision was performed in two cases and localization & excisional biopsy was performed in an occult case. Pathologic report of the cases revealed them as DCIS in a fibroadenoma.

Possibility of malignancy cannot be excluded in fibroadenomas especially in case with calcifications within the mass in the radiological study or with atypical cells presented in the cytology. Cytology and ultrasonogram should be used to evaluate fibroadenomas. If there are any suspicion of malignancy, excisional biopsy should be performed to confirm the benign state.