Fibroadenoma of the breast in a man associated with adenocarcinoma of the rectum and polyposis coli.

Fibroadenoma of the breast is an uncommon cause of breast lumps in men. Only a few cases have been reported in the literature, the majority of which were prescribed estrogen. We present herein the first case of a fibroadenoma of the breast in a 68-year-old man with adenocarcinoma of the rectum and polyposis coli. In this case, there was neither estrogen treatment nor any other medications which have been discussed in the literature as inducing fibroadenomas. Fibroadenomas in men without hormone treatment and with normal hormone levels are extremely rare and the developmental mechanism of the breast fibroadenoma in this man is under question.