Colonic Ganglioneuroma: A Combined Single-Institution Experience and Review of the Literature of Forty-Three Patients.

Ganglioneuromas (GNs) are rare, benign tumors composed of ganglion cells, nerve fibers, and glial cells. Three types of colonic GN lesions exist: polypoid GNs, ganglioneuromatous polyposis, and diffuse ganglioneuromatosis. Less than 100 cases of GN are documented in the literature. A 10-year retrospective search of the pathology database at our institution identified eight cases of colonic GNs. All cases were incidental. Seven of the eight cases presented with colonoscopy findings of small sessile polyps (ranging between 0.1 and 0.7 cm) treated with polypectomy, whereas one case showed a 4 cm partially circumferential and partially obstructing mass in the ascending colon, treated with right hemicolectomy. Almost two-thirds of the cases (5/8) demonstrated associated diverticulosis. All cases were positive for S100 protein and Synaptophysin via immunohistochemistry (IHC). No syndromic association was identified in any of the cases. We also conducted a comprehensive review using PubMed to identify cases of colonic GN reported in the literature. In total, 173 studies were retrieved, among which 36 articles met our inclusion criteria (35 patients and 3 cases on animals). We conclude that while most GNs are incidental and solitary small sessile lesions, many can be diffuse and associated with syndromes. In these cases, the tumor can result in bowel obstruction simulating adenocarcinoma.