granular cell tumor

granular cell tumor A typically benign, uncommon tumor characterized by the presence of cells with a striking granularity of the cytoplasm when viewed under the microscope. The tumors are derived from neural cells, and the granularity of the cytoplasm is due to the accumulation of secondary lysosomes. Granular cell tumors are generally slowgrowing, solitary, painless nodules that can occur anywhere in the body. Malignant granular cell tumors occur rarely.