The problem of carcinoma developing in a fibroadenoma: recent experience at Memorial Hospital.

Fourteen new cases of unsuspected carcinoma developing in fibroadenomas are reported with a detailed analysis of their preoperative findings; histopathology, the results of varying surgical procedures and a three month to twenty-six year follow-up. The majority of lesions were lobular carcinoma in situ (71%) and 29% of all cases were found to have carcinoma of the contralateral breast. Our study suggests that for invasive carcinoma within a fibroadenoma complete mastectomy is warranted in virtually all instances while noninvasive disease treated by complete mastectomy is essentially curative. Contralateral breast biopsy at the time of diagnosis with a careful life-time follow-up are appropriate because of the high risk of contralateral invasive coarcinoma. There seemed to be no evidence of striking or unusual epithelial hyperplasia in the breast tissue adjacent to fibroadenomas that contained carcinoma suggesting that the carcinomas are not intrinsically different from those not related to fibroadenomas.