Carcinoid Tumor Development in Crohn’s Disease

Abstract

Introduction: A 2007 study at Vanderbilt University indicated that carcinoid tumors are 15 times more common in patients with Crohn’s disease (CD). There has previously been debate in the literature about the exact pathophysiological link. It takes approximately 10 years for enterochromaffin-like cell (ECL) hyperplasia to develop into a carcinoid. A 1998 study by Szabo showed that carcinoid tumors are found more frequently in an inflamed appendix (0.24%) compared to an appendix from autopsy (0.03%). Several inflammatory cytokines involved with CD, such as interleukin 12, tumor necrosis factor alpha, and interferon gamma contribute to carcinoid tumor formation. This case report adds to the growing body of literature illustrating a possible link between the inflammatory environment of CD and the development of a gastrointestinal carcinoid tumor. A 37-year-old female first diagnosed with CD via colonoscopy in 2001 was initially treated with azathioprine and mesalamine. Her symptoms were never completely controlled on this regimen. In 2008, the patient stopped all medications and follow-up. In 2013, she was admitted for a Crohn’s flare, and a high-grade small bowel obstruction was noted on CT and MR enterography. She was loaded with certolizumab and she restarted azathioprine. One month later, her symptoms persisted, and she underwent an 18-cm jejunal resection. An esophagogastroduodenoscopy and a colonoscopy were scheduled 2 months later to evaluate the extent of her disease and to work up severe weight loss. EGD was normal, but a 4-mm rectal polyploid-appearing lesion with yellow hue was found during colonoscopy and biopsied in a bite-on-bite fashion. Pathology revealed a carcinoid tumor strongly positive for synaptophysin (SP11) and negative for chromogranin (LK2H10). Researchers have hypothesized that the inflammation and hyperplasia caused by CD predisposes patients to develop carcinoid tumors. The incidence of carcinoid among CD patients appears to be higher than would be expected, possibly as a consequence of distant inflammatory cytokine effects. Radiographically, carcinoid tumors may appear like Crohn’s disease. Histologically, carcinoid tumors also appear similar to CD with fibrosis and wall thickening. Due to these similarities, the incidence of carcinoid among CD patients may actually be higher than the less than 50 case reports that exist in the literature. This case adds to the growing body of evidence illustrating the development of carcinoid tumor among CD patients.