Imaging features of granular cell tumor in the breast: Case report.

RATIONALE Granular cell tumor of the breast (GCTB) is a benign rare tumor. There are limited reports on its imaging manifestations. GCTB is often misdiagnosed as breast cancer, which results in unnecessary radical mastectomy and excessive treatment. In this article, we have reported a case of a 56-year-old postmenopausal woman with GCTB and highlighted the imaging features to differentiate this rare tumor from breast cancer. PATIENT CONCERNS A 56-year-old postmenopausal patient had a chief complaint of a subcutaneous nodule in the upper outer quadrant of her right breast for 2 months. She underwent physical examination, color Doppler ultrasonography, mammography, magnetic resonance, and postoperative pathology. DIAGNOSES The final diagnosis was GCTB. The tumor cells were intermingled with the fibrous stroma and normal breast parenchyma and showed positive immunoreaction to S-100, CD68, and neuron-specific enolase. INTERVENTIONS The patient underwent lumpectomy and sentinel lymph node biopsy. OUTCOMES The patient recovered well after lumpectomy and had no complications during the 2-year follow-up. LESSONS There are some important imaging features of GCTB that can be used to distinguish it from breast carcinoma to reduce misdiagnosis.