Granular cell tumor of colon: report of a case and review of literature.

Granular cell tumor (GCT) is uncommon in the colon and rectum. Here we report a case of GCT in the transverse colon. A 48-year-old male patient underwent a screening colonoscopy. A yellowish sessile lesion, about 4 mm in diameter, was found in the transverse colon. An endoscopic snare resection was performed without complication. Histological examination revealed the tumor consisted of plump neoplastic cells with abundant granular eosinophilic cytoplasm containing acidophilic periodic acid Schiff-positive, diastase-resistant granules. Immunohistochemical analysis showed the tumor cells expressed S-100 protein and neuron-specific enolase. Thus, the resected tumor was diagnosed as a GCT. Since GCTs are usually benign, endoscopic resection constitutes an easy and safe treatment. Colonoscopists should consider the possibility of GCT in the differential diagnosis of submucosal tumors of the colon.