Mediastinal Granular Cell Tumor
Abrikossoff tumor; Granular cell myoblastoma
Granular cell tumors have been known to exist since the mid-nineteenth century when the first cases were reported in the German literature. Initially believed to be of myoblastic origin, application of electron microscopy and immunohistochemistry has subsequently shown increasing evidence that granular cell tumors are of neural origin and likely derived from Schwann cells. The vast majority of granular cell tumors occur in the head and neck area, most commonly the tongue, but almost any anatomic location can harbor these lesions. The majority of granular cell tumors are benign neoplasms; malignant variants are rare and estimated to represent 1–2% of granular cell tumors and 0.2% of all soft tissue sarcomas. A small subset of patients present with multiple lesions either in the same organ or in multiple different sites (Ordonez 1999; Fanburg-Smith et al. 1998; Marchevsky 1999).