Breast and pectoralis musculo-aponeurotic fibromatosis: two independent lesions occurring in the same patient. A case report.

We report the first case of primitive breast fibromatosis associated with a synchronous independent musculo-aponeurotic fibromatosis of the omolateral pectoralis major muscle in an otherwise healthy 29-year-old woman without clinical evidence of any genetic syndrome. The primary occurrence of the two lesions was supported by the absence of any macroscopic and microscopic connection. The present case suggests that a pre- or intraoperative frozen section diagnosis of breast fibromatosis should lead the surgeon and pathologist to exclude an independent fibromatosis of the underlying musculo-aponeurotic fascia.