Desmoid tumors (fibromatoses) of the breast: a 25-year experience.

BACKGROUND: Breast desmoid tumors are rare and often clinically mistaken for carcinoma. We reviewed our 25-year institutional experience with breast desmoid tumors.
METHODS: A search of pathology and sarcoma databases (1982-2006) identified 32 patients with pathologically confirmed breast desmoids. Records were retrospectively reviewed.
RESULTS: Median presentation age was 45 years (range, 22-76). Eight patients (25%) had prior history of breast cancer and 14 (44%) of breast surgery, with desmoids diagnosed a median of 24 months postoperatively. All presented with physical findings. Mammography visualized the mass in 6/16, ultrasound in 9/9, and magnetic resonance imaging (MRI) in 8/8 patients in whom it was performed. In 15 patients with attempted needle biopsy, fine needle aspiration was inconclusive (9/9 patients), and core biopsy demonstrated a spindle cell lesion (6/7 patients). Treatment was surgical, with median tumor size of 2.5 cm (range, 0.3-15). Eight patients (29%) had recurring tumors at a median 15 months. Patients with recurring tumors were younger (median age: 28 vs. 46 years, p = 0.03). A trend toward more frequent recurrences in patients with positive (5/9 patients) versus negative (3/19 patients) margins (p = 0.07) and larger tumors (p = 0.12) was observed.
CONCLUSIONS: In our series, breast desmoids presented as palpable masses suspicious for carcinoma clinically and radiographically. Therapy remains primarily surgical, and core biopsy aided in operative planning. Recurrences are common, with younger age and possibly positive margin status and larger tumor size associated with increased risk of recurrence. As 5/9 patients with positive and 3/19 patients with negative margins experienced recurrences, clinical judgment should be used prior to extensive and potentially deforming resections.