Fibromatosis of the breast.

A case of fibromatosis of the breast occurring in a 37-year-old woman is described. Only 15 cases of this type have been previously reported. In 5 of these cases there was also involvement of the underlying pectoral muscles, raising the possibility that some of these may have been of pectoral musculoaponeurotic origin. Two of the previously reported cases occurred in patients with Gardner's syndrome and 1 in a patient with "familial muticentric fibromatosis." It is anticipated that fibromatosis of the breast will behave in a similar fashion to fibromatosis occurring in other sites; i.e., as a local aggressive lesion which exhibits a high incidence of local recurrence following incomplete excision.