Granular cell tumor of the breast in a 17-year-old female: A case report

Granular Cell Tumors (GCTs) are rare soft tissue neoplasms originating from Schwann cells, often benign but mimicking breast carcinoma clinically and radiologically. A 17-year-old female with a second-degree family history of breast cancer presented with a painful left breast mass (∼3 cm) persisting for three years. Initial evaluation with fine needle aspiration (FNA) suggested a benign lipoma, but imaging reported BIRADS IV mass. Mammography revealed an ovoid mass with irregular margins, Sono-mammogram reported heterogeneous slightly lobulated mass with excentric sonolucent of 3 x 2.4 × 1.8 cm, no increased vascularity on sono-doppler and core needle biopsy confirmed a GCT, positive for S-100 and CD68. The patient was taken to the operating room for surgical excision. A 4 cm curvilinear incision was made over the left breast mass, just lateral to the nipple at the 3 o'clock position. En-bloc excision of the mass was carried out with 1 cm margins. The specimen was removed and sent for frozen section analysis that confirmed the cytological diagnosis of a granular cell tumor with clear margins. The excised mass was sent for permanent section to pathology. Final histopathology confirmed a benign GCT with free margins. Due to the infiltrative nature of the tumor, a second excision in similar fashion was required to obtain wider margins, which was uneventful. Clear margins were pursued due to the tumor's infiltrative nature and patient's family history of breast cancer, despite the low risk of recurrence with positive margins. The patient remains clinically disease-free at three-year follow-up. Granular cell tumors of the breast, though benign, are often mistaken for carcinoma due to their clinical similarity. Complete excision with clear margins, which may require re-excision due to their infiltrative nature, is crucial to prevent recurrence.