Recurrence risk and margin status in granular cell tumors of the breast: a clinicopathologic study of 13 patients.

CONTEXT: Granular cell tumors (GCTs) of the breast are rare neoplasms that mimic epithelial malignancy clinically and rarely occur in association with it. Granular cell tumors of the breast are not infrequently excised with positive margins. Reports describing risk of recurrence including data on margin status and follow-up are lacking. OBJECTIVE: To review our series of GCTs of the breast to determine the risk of recurrence if excised with positive or close margins. DESIGN: Cases of GCT of the breast were reviewed. Margin status of specimens was recorded as positive, close (<1 mm), and negative. RESULTS: Thirteen female patients with GCT of the breast were identified. Mean patient age at presentation was 45 years. Seventy-seven percent of patients were African American and 23% were white. African American patients presented on average 13 years earlier than white patients. Average tumor size was 1.22 cm. Fifteen percent of lesions had positive margins on excisional biopsy or lumpectomy and 31% had tumor cells within 1 mm of the margin. One of 13 patients (8%) had coexistent invasive ductal carcinoma. Average follow-up for the entire group was 77 months. Patients with positive margins remained free of tumor progression or recurrence for 89 months and patients with close margins also remained disease free during a 64-month follow-up period. No tumors recurred out of the entire group. CONCLUSION: Granular cell tumors of the breast have little long-term risk for recurrence, even when excised with positive margins. Surgical evaluation after nonexcisional biopsy may still be indicated to assess for the possible association of colocalized carcinoma.