Bilateral breast fibromatosis: case report and review of the literature.

Fibromatosis or desmoid tumor is a benign, slow-growing fibroblastic neoplasm originating from musculoaponeurotic stromal elements. These tumors are characterized by an infiltrative and locally aggressive growth pattern, frequent recurrences, but no metastatic potential. The etiology is unknown, but these tumors have been associated with trauma and genetic disorders. Breast fibromatosis is exceedingly rare and often misdiagnosed, comprising only 0.2% of breast tumors. Clinically, it might mimic other breast lesions, such as carcinoma. Only approximately 6 case series and 100 case reports of this disorder affecting the breast are documented, and only 5 cases of bilateral breast fibromatosis have been reported. We describe the case of a 20-year-old woman who presented to our institution with firm, nontender masses palpable in both breasts. Prior ultrasound was suspicious for carcinoma, and breast core biopsies were suggestive of phyllodes tumor. An excisional biopsy was necessary to establish the diagnosis of breast fibromatosis for both masses. A review of articles published on desmoid tumors and breast fibromatosis was performed with emphasis on articles published in the last 10 years. Fibromatosis should be considered in the differential diagnosis of patients presenting with hard breast lumps suspicious of other diseases.