Although colorectal granular cell tumors (GCTs) are rare, their incidental finding has increased as the use of diagnostic colonoscopy has become more common. Here we describe the case of a 41-yr-old man with a GCT in the descending colon that was detected after a screening colonoscopy. Endoscopic examination revealed a yellowish submucosal tumor, 13x12 mm in diameter, in the descending colon. Endoscopic mucosal resection (EMR) followed by histological examination revealed that the tumor was composed of plump histiocyte-like cells with an abundant granular eosinophilic cytoplasm and small round nuclei. The tumor cells expressed S-100 protein and stained with periodic acid-Schiff, but were negative for desmin and cytokeratin. The resected tumor was diagnosed as a GCT. Colonoscopists should consider the possibility of GCT in the differential diagnosis of yellowish submucosal tumors of the colon. In such patients, EMR seems to be a feasible and safe approach for diagnosis and treatment.
Adult ; *Colon, Descending/pathology ; Colonic Neoplasms/diagnosis/*pathology/surgery ; Colonoscopy ; Diagnosis, Differential ; Granular Cell Tumor/diagnosis/*pathology/surgery ; Humans ; Male ; S100 Proteins/metabolism

Adult ; Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Appendectomy ; Appendiceal Neoplasms ; complications ; metabolism ; pathology ; surgery ; Appendicitis ; etiology ; surgery ; Diagnosis, Differential ; Female ; Granular Cell Tumor ; complications ; metabolism ; pathology ; surgery ; Humans ; Paraganglioma ; metabolism ; pathology ; Phosphopyruvate Hydratase ; metabolism ; S100 Proteins ; metabolism

Aged ; Biomarkers ; metabolism ; Carcinoid Tumor ; metabolism ; pathology ; Carcinoma, Endometrioid ; metabolism ; pathology ; surgery ; Diagnosis, Differential ; Female ; Granular Cell Tumor ; metabolism ; pathology ; Humans ; Hysterectomy ; methods ; Keratin-7 ; metabolism ; Keratins ; metabolism ; Krukenberg Tumor ; metabolism ; pathology ; Middle Aged ; Mucin-1 ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; surgery ; Sertoli Cell Tumor ; metabolism ; pathology ; Sex Cord-Gonadal Stromal Tumors ; metabolism ; pathology ; surgery