Fine needle aspiration cytology diagnosis of a cutaneous granular cell tumor in a 7-year-old child. A case report

BACKGROUND: Granular cell tumors are neoplasms of uncertain histogenesis, although a neural origin is favored. Most reports on the cytologic features of granular cell tumors have been on lesions from the breast or respiratory tract. However, there are only a few reports on fine needle aspiration (FNA) cytologic diagnosis of cutaneous or soft tissue granular cell tumors. CASE: A 7-year-old girl presented with a skin lesion on her right forearm of one year's duration. The FNA smears showed sheets and clusters of oval to polygonal cells with an abundant amount of granular cytoplasm. Many single, scattered cells with similar morphology were seen in the background. Immunostaining for S-100 protein showed granular cytoplasmic positivity. The tumor was diagnosed as a benign granular cell tumor. The histopathology report on the excised lesion confirmed the FNA diagnosis. CONCLUSION: The cytopathologic features of granular cell tumors presenting as skin lesions are distinctive enough to allow a correct diagnosis on FNA cytology.