Granular Cell Variant of Epithelioid Cell HistiocytomaRabkin, Michael S. MD, PhD*; Vukmer, Tyler DO†American Journal of Dermatopathology: October 2012 - Volume 34 - Issue 7 - p 766–769 doi: 10.1097/DAD.0b013e31825aa415 Extraordinary Case Report Abstract Author Information Abstract Abstract: Classic granular cell tumors (GCTs) stain strongly and uniformly positive for S100 protein and are believed to show Schwann cell derivation. Polypoid cutaneous tumors composed of cells with large nuclei and abundant granular cytoplasm that do not stain for S100 protein or show apparent Schwannian differentiation have been reported by several groups under names including “primitive polypoid granular cell tumors,” “dermal nonneural granular cell tumor,” and “primitive nonneural granular cell tumors of skin.” We report a polypoid tumor composed of S100-negative epithelioid cells with abundant eosinophilic granular cytoplasm that meets diagnostic criteria for (primitive polypoid dermal) nonneural GCT but also meets criteria for a granular cell variant of epithelioid cell histiocytoma. We have identified a single previous report of a similar lesion. We report the immunohistochemical characteristics of these lesions and address how they are best classified. Author Information *Rabkin Dermatopathology Laboratory, P.C., Tarentum, PA †Largo Medical Center, Largo, FL. Reprints: Michael S. Rabkin, MD, PhD, Rabkin Dermatopathology Laboratory, P.C., 419 East Second Avenue, Tarentum, PA 15084 (e-mail: firstname.lastname@example.org). The authors declare no funding or conflicts of interest. © 2012 Lippincott Williams & Wilkins, Inc.