Abstract

Desmoid-type fibromatosis of the breast is a rare, locally aggressive stromal tumor. This lesion is observed in 0.2% of all breast tumors, often occurs between the ages of 25 and 45 and the sex ratio is 1: 2 (male: female). In this study, we report a case of a 57-year-old woman with breast fibromatosis, which has been mimicking breast carcinoma. On physical examination, there was an irregularly shaped mass lesion of approximately 3x2 cm fixed to the chest wall in the upper outer quadrant of the left breast. On mammography, an increase in opacity covered by fibroglandular tissue was observed in the outer middle part of the left breast. On ultrasound examination, a heterogeneous hypoechoic solid lesion with microcalcifications in places and 32x10mm in size with irregular borders and internal echoes were observed in the upper outer quadrant of the left breast. (BIRADS 4). Since the tru-cut biopsy could not differentiate between Fibromatosis-like Metaplastic Breast Carcinoma and Desmoid Fibromatosis, an excisional biopsy was performed under general anaesthesia. Wide local excision was performed due to positive surgical margins. In conclusion, desmoid-type fibromatosis has nonspecific physical examination findings and radiological imaging and is confused with malignancy. The primary treatment of this lesion is excision with a negative surgical margin