We report a case of primary granular cell tumor of the breast. A 40s female seen for an upper inner-quadrant right-breast mass was found in preoperative fine-needle aspiration cytology (FNAC) to have clustered or disassociated tumor cells with abundant granular cytoplasm and small oval nuclei. Cell boundaries were ill-defined. Extracellular granular materials were seen in the background. Histologically, we diagnosed granular cell tumor of the breast. Clinically, granular cell tumors mimic breast carcinoma, and pathologists should bear this in mind in FNAC to avoid a misdiagnosis of breast carcinoma.
