Fibromatosis of the breast in a 52-year-old man (2010: 10b).

Fibromatosis is a proliferation of fibroblastic and miofibroblastic cells that primarily originate from the fascia or aponeuroses of the abdominal wall. This entity has no potential metastatic risk, but can reappear locally. In rare cases it may develop in the breast, and it is extremely uncommon in the male breast.