Granular cell tumor of the tongue (Abrikossoff's tumor). A case report and review of the literature.

Granular cell tumor (GCT), also known as Abrikossoff's tumor, is a relatively uncommon neoplasm presenting as a benign, single, well-circumscribed nodule, usually arising on the tongue. Histologically, GCT shows numerous strands of large polyhedral granular cells, separated by collagen bundles, with no evidence of encapsulation. Recurrences may occur following inadequate excision. A 32-year-old woman, presenting a non-painful nodule embedded in the chorion of her tongue, underwent a first excisional biopsy which revealed a GCT and the margins of the bioptic sample appeared free. Immunohistochemistry for protein S-100 revealed the tumor cells invading the margins of the sample. A second intervention was made to excise the possible remaining neoplastic tissue. This case, owing to its uncommon clinical appearance, seemed particularly interesting. Immunohistochemical assay for S-100, whenever a CGR is suspected, is always mandatory to discover tumor cells infiltrating the margins of the sample. Furthermore, immunohistochemical assay can make the diagnosis more precise excluding other more serious tumors which could arise in the oral cavity. In any event, the patient should be reassured of the benign nature of the tumor and a careful follow-up is necessary in order to diagnose relapses.