Malignant Granular Cell Tumor with an Unusually Long Clinical Course: An Autopsy Case with Review of Literature

Malignant granular cell tumor is a rare malignant soft tissue neoplasm that occurs at various sites [1-18] and accounts for 1–2% of granular cell tumors [1]. Granular cell tumors are generally divided into 3 categories according to the diagnostic criteria proposed by Fanburg-Smith et al. [1], although these criteria for malignancy are still debated among pathologists. Malignant granular cell tumors have been shown to be of Schwann cell origin [4,5], although it has not yet been clearly determined whether malignant tumors arise denovo or originate from preexisting benign granular cell tumors. Furthermore, no therapeutic strategy against this tumor has yet been established, although some authors have reported that the tumor is resistant to systemic chemotherapy and that surgical resection is the best course of action [17].