Granular cell tumor of the breast: a case report

A granular cell tumor involving the breast parenchyma was first described by Abrikossoff in 1931. Localization of this lesion to the breast is very rare, accounting for between 5% and 15% of all granular cell tumor cases. We present this case because of the rarity of this tumor. It is frequently confused with breast carcinoma on clinical and radiological examination, and its diagnosis can therefore be challenging for clinicians, radiologists and pathologists. We report the case of a 32-year-old Moroccan woman who presented with a palpable mass in her right breast. Mammography and ultrasound examination revealed a heterogeneous, irregular and poorly limited mass, located at the union of the outer quadrants of her right breast. The mass was in contact with her latissimus dorsi and suspicious for malignancy. A histological examination combined with immunohistochemical study revealed it to be a granular cell tumor. Although a granular cell tumor of the breast is a rare breast neoplasm, it should be considered in the differential diagnosis of benign and malignant lesions. Pathologists should bear in mind a granular cell tumor when examining material containing cells with abundant granular cytoplasm to avoid misdiagnosing breast carcinoma, which could lead to unnecessary surgery.