Pediatric colonic adenocarcinoma: A deceptive case of gastroenteritis and constipation.

Adenocarcinoma of the colon is a rare diagnosis in pediatric patients. We present a previously healthy 15-year-old female who began experiencing escalating colicky abdominal pain and associated vomiting over 2 weeks in the setting of presumed acute gastroenteritis. A computed tomography scan revealed an obstruction in her descending colon. A multidisciplinary decision was made to perform a colonoscopy upon which a large, circumferential, friable lesion was discovered 40 cm from the anus. A colon decompression catheter was successfully inserted following controlled radial expansion (CRE) Balloon dilation to 13.5 mm beyond the mass, resulting in a significant discharge of fluid and gas. The patient underwent hemicolectomy with mass resection and colostomy. Biopsies confirmed poorly differentiated adenocarcinoma with "napkin-ring" morphology and positive lymph node metastasis with extranodal extension.