Granular cell tumor of the breast: a rare lesion resembling breast cancer.

Granular cell tumor (GCT) is an uncommon, usually benign tumor that occasionally involves the breast. It is possibly of neural origin (Schwann cells) and usually occurs in premenopausal black women. Physical examination, mammographic, ultrasonographic findings and pathologic examination may suggest breast malignancy. Positive immunohistochemical staining of the cells for S-100 protein, NSE, and CEA is indicative of GCT. Surgical treatment of choice is wide local excision. We report a case of granular cell tumor of a female breast. A 52-yr-old white woman had a palpable mass close to her right axilla. Computer tomography (CT) showed a 3.74 cm mass in the mammary tail of Spencer. The findings were suspicious for malignancy and the lesion was widely resected. Pathologic examination showed granular cell tumor.