Granular cell tumors

Granular cell tumour encopasses a heterogeneous group of entities characterized by the proliferation of large cells with granular eosinophilic cytoplasm. We report the case of a 39-year-old woman, who presented with a single pigmented surface nodule of the arm, measuring 2 cm of diameter. She underwent a surgical excision. The microscopic examination showed a lobulated dermal proliferation, with X limitation, and constituted by rounded globulous cells, rarely spindle-shaped without necrosis. The cytoplasm had abundant eosinophilic PAS positive granules. The nuclei were rounded without atypia. The mitotic index was 2 mitoses/10 high power fields. The immunohistochemical study showed positivity for P-S100. This all lead to the diagnosis of granular cell tumour without histological criteria of malignancy. The granular cell tumour is mostly localized in the head and the neck. It is more frequent in woman with a sex ratio of 3/1 and a peak of frequency between the 3rd and 5th decades of life. It is often benign but malignant forms have been reported in 1 to 3% of the cases. Because of the potential for recurrence and the morphologic overlap between benign and malignant granular cell tumours, complete excision is recommended. The specificity of this observation is to report one case of this rare entity and discuss its histogenesis and criteria of malignancy. © Springer-Verlag France 2010.