Synchronous colon cancer presenting as toxic megacolon in a patient with ulcerative colitis: A case report

The incidence of colorectal cancer in patients with inflammatory bowel disease is greater than the general population. Of those with inflammatory bowel disease, synchronous cancers are more common in ulcerative colitis than in Crohn's disease. It is rare for synchronous cancer to present as toxic megacolon in a patient with concomitant inflammatory bowel disease, specifically ulcerative colitis.

In this report, we describe the clinical presentation of a 22-year-old female, who presented with toxic megacolon ultimately requiring total abdominal colectomy with end-ileostomy and a final pathology of two synchronous colon cancers, despite normal colonoscopy one year prior. The postoperative period was unremarkable, and the patient was referred to medical oncology to pursue adjuvant treatment.

Due to the increased incidence of colorectal cancer in patients with ulcerative colitis, screening colonoscopies are typically recommended at more frequent intervals than the general population. Toxic megacolon as the presentation for colon cancer in patients with underlying ulcerative colitis is exceedingly rare. To our knowledge, this is the first case reported of synchronous colon cancer presenting as toxic megacolon in a patient with ulcerative colitis and recent negative screening colonoscopy.

Colorectal cancer should always be high in the differential diagnosis for patients with ulcerative colitis regardless of the age. The principles of oncologic resection for colorectal cancer should be followed during colonic resections in patients with ulcerative colitis, even in the acute setting.