Malignant granular cell tumor of soft tissues - A study of two new cases

We describe 2 cases of malignant granular cell tumor. A marked discrepancy exists concerning the criteria of malignancy of this rare entity, which was diagnosed in male patients aged 41 and 52 years, respectively. They presen ted with tumors measuring more then 3.5 cm; one arose in the dermis and sub cutaneous tissue in the region of the scapula, whereas the other was situat ed in deeper soft tissue in the pelvis. One case, with previous diagnosis o f benign granular cell tumor, presented local recurrence 2 years after the initial diagnosis. The other case presented a fascicular pattern of growth invading adjacent muscular tissue, Both neoplasms were composed of polygona l and spindle cells, showing abundant cytoplasm, vesicular nuclei with larg e nucleoli, high nuclear-to-cytoplasmic ratio, and pleomorphism. Immunohist ochemically, the neoplastic cells of both cases were positive for vimentin, S100 protein, neuron-specific enolase (NSE), and CD68. In addition, high e xpression of p53 and MiB1 (Ki67) was detected. Herein, we discuss the morph ologic and immunohistochemical criteria of malignancy of granular cell tumo rs.