Granular cell tumor of a digital nerve.

Granular cell tumor is an infrequently encountered albeit not rare neoplasm considered to be of neuroectodermal origin. An example of a benign granular cell tumor originating within a digital nerve is presented. The authors employed routine light microscopic techniques and immunostaining which demonstrate features of the granular cells reflecting structural and functional characteristics of Schwann's cells and support neuroectodermal derivation. Granular cell tumor is ubiquitous in location but occurs more frequently in tongue, skin and subcutaneous tissue. Clinical features are not specific, and a histologic evaluation is required for diagnosis. Circumscription and lack of cellular pleomorphism define a benign process. However, irrespective of its histologic appearance, the biologic potential is uncertain. Complete excision suffices as treatment for benign tumors.