Supplementary Material for: Case report of a benign granular cell tumor resembling breast carcinoma in a young woman: a diagnostic challenge

' Introduction '
Granular cell tumors (GCTs) are uncommon, low-grade Schwann cell tumors found in the skin, soft tissue, and mucosal surfaces of the oral, gastrointestinal, and respiratory tracts. 1 in 1000 breast cancer cases is GCT. Just 1%–2% of GCTs are malignant granular cell tumors (MGCTs).
' Case presentation '
This case report presents the clinical details and outcomes of a 34-year-old woman with a main concern of a palpable mass and pain in her right breast. In the clinical examination, we found a 1.5 *2 cm palpable mass in her right breast with no axillary lymph node detection. The primary diagnosis was a benign GCT mimicking carcinoma of the breast. Upon evaluation, the mass was confirmed to be a benign granular cell tumor (GCT) through pathology. The patient underwent breast-conserving surgery (BCS) and sentinel lymph node dissection (SLND) at the Cancer Research Center of Shahid Beheshti University of Medical Sciences on 30th November 2022. The surgical margins were found to be free of tumors, and there was no involvement of skin or axillary lymph nodes. The patient had a positive post-operative outcome, with no complications observed.
'Conclusion'
The case highlights the importance of accurate diagnosis and appropriate surgical planning to avoid invasive procedures and unnecessary radical surgeries in cases of benign GCT mimicking carcinoma of the breast.