Case for diagnosis. Granular cell tumor.

Granular cell tumor is a rare benign neoplasm of neural origin. We report the case of a female patient, 27 years old presenting a brown-red nodule in the right arm, which pathological examination showed to be formed by polygonal cells with eosinophilic granular cytoplasm and immunohistochemistry positive for S100 protein and CD68. Granular cell tumor is usually solitary and in half the cases located in the head and neck areas, 30% of these in the tongue. It is most frequent between the third and fifth decades of life in women and people of African-American ethnicity. Its origination is controversial, including the possible origins in muscle, fibroblasts, neural crest, neural sheath or histiocytes. The positivity for S-100 and CD68 suggest the neural origin.