Fibromatosis of the Breast: A Case Report

ABSTRACT

Fibromatosis of the breast is a rare tumor. We describe here a case of mammary fibromatosis in a 37-year-old woman. The mass from the right breast was 3 cm at the greatest dimension. The lesion was poorly circumscribed, firm and white-gray on the cut surface. Histologically, the lesion infiltrated into the lobules of the breast, and the tumor was composed of relatively uniform fibroblasts and collagen. Neither mitotic activity nor cellular atypia was seen. On the immunohistochemistry, the cells were positive for vimentin and they were focally positive for smooth muscle actin. Staining results for estrogen receptor and progesterone receptor were negative.