Introduction: Isolated large intestinal involvement of neurofibromatosis is a fairly rare clinical finding. Herein, we present a case of colonic ganglioneuromas causing pseudo-obstruction in a patient with neurofibromatosis without other gastrointestinal tract findings. Case Description/Methods: A 59-year-old male with a history of neurofibromatosis and gastroesophageal reflux disease (GERD) on pantoprazole presented to our clinic for a follow-up visit. Despite medical management, he reported worsening of his GERD symptoms, namely epigastric pain and bloating. He was scheduled for surveillance esophagogastroduodenoscopy (EGD) and colonoscopy for colon cancer screening. On the morning of the procedure, he was afebrile and vital signs were stable upon arrival. EGD showed gastritis, but was otherwise unremarkable. Colonoscopy revealed a ∼7cm pedunculated polyp in the ascending colon and a 4cm flat polyp and 1 pedunculated polyp in the transverse colon. Pathology from the polyps showed submucosal lipomas as well as ganglioneuroma with associated acute colonic ulceration. Due to the size and location of the ascending colon polyp, it was thought to be contributing to his symptoms of obstruction. At a recent clinic follow-up visit, he was doing well and endorsed improvement in his reflux, bloating, and epigastric pain. He was also having regular bowel movements and denied constipation. The patient was scheduled for repeat surveillance colonoscopy to be performed in 2 years. Discussion: Neurofibromatosis type 1 (NF-1), also referred to as von Recklinghausen disease, is an autosomal dominant disorder caused by mutations in the NF-1 tumor suppressor gene. While the clinical presentation of NF-1 varies based on the specific mutation, common presenting symptoms include café-au-lait spots, Lisch nodules, neurofibromas, and optic gliomas. Gastrointestinal involvement has also been reported ranging from neurofibromas in the liver to the bowel. Inflammatory fibroid polyps are most commonly found in the stomach and small intestine; isolated colonic polyps are rarer, but case reports have documented findings of neurofibromas in the large intestine. Our patient has a unique presentation of polyps associated with NF solely found in the colon. Based on the location of involvement, symptoms may include abdominal pain, distension, and constipation. It is important that these patients undergo routine surveillance due to the risk of malignant transformation.Figure 1.: ∼7cm pedunculated polyp in the ascending colon.