Malignant granular cell tumor of the median nerve: a case report with a literature review of 157 cases

Malignant granular cell tumors are an extremely rare, high-grade sarcoma with a schwannian phenotype and are composed of malignant granular cells with cytoplasmic lysosomal inclusion. To date, 157 cases of malignant granular cell tumors have been reported. We report the first case of a malignant granular cell tumor arising from the digital nerve to the median nerve in the palm, and we review the 157 previously reported cases and summarize the clinical profile, treatment, and outcome of this tumor. The median age, tumor size, and follow-up periods were 51 years, 6 cm, and 24 months respectively. With respect to the oncological result, 53 patients (33.8%) had no evidence for disease, 31 (19.7%) were alive with the disease, and 51 (32.5%) died because of the disease. Our case report indicates that rare malignant tumors can arise from the digital nerve to the median nerve in the palm, an anatomical site that is usually affected by benign lesions. Exhaustive discussions between surgeons and pathologists are necessary for the treatment of this rare malignant tumor.