Malignant granular cell tumor.

We report a case of malignant granular cell tumor of the chest wall that recurred in the right breast with axillary lymph node metastases. The recurrent tumor clinically and grossly mimicked a breast carcinoma. Electron microscopy and immunohistochemical techniques were used to confirm the cytologic and histologic diagnosis of granular cell tumor. The importance of true metastases in the diagnosis of malignant granular cell tumor and their differential diagnosis are discussed.