S3969 Granular Cell Tumor of the Colon: A Rare Finding on Routine Colonoscopy

Introduction: Granular cell tumors (GCTs) are uncommon, typically benign neoplasms of neural origin most frequently found in the head and neck region. Gastrointestinal involvement is rare, with the colon being an especially rare site. Here, we present a case of a sigmoid colon GCT discovered incidentally during routine colon cancer surveillance in a young healthy adult man. Case Description/Methods: A 30-year-old man presented for routine surveillance colonoscopy due to a history of high-risk polyps. Colonoscopy revealed a 6 mm sessile polyp in the sigmoid colon. The polyp was completely removed with a cold snare. Histopathological examination revealed a granular cell tumor, characterized by cells with granular eosinophilic cytoplasm and immunohistochemical staining positive for S-100, confirming neural origin. There was no evidence of malignancy. The patient is scheduled for repeat colonoscopy in one year for surveillance. Discussion: Granular cell tumors in the colon are very rare, with very few cases documented in the literature. Their endoscopic appearance can mimic more common lesions, such as adenomatous polyps. Although typically benign, incomplete resection and uncertainty in behavior requires close follow-up. This case underscores the importance of histologic evaluation of all resected polyps and serves as a reminder to keep rare entities like GCTs in the differential for colonic polyps.