Hereditary Nonpolyposis Colorectal Cancer in Association with Crohn's Disease and Lynch Syndrome: The Importance of a Strict Endoscopic Surveillance.

Crohn's disease (CD) and Lynch syndrome (LS) are two different entities, yet both are associated with increased risk of colorectal cancer (CRC). We present the case of a young female patient in long-standing remission of her ileocolonic luminal CD, and a family history of LS on a regular short interval (every 2 years) colonoscopy surveillance. Despite normal blood tests, fecal calprotectin, and ileocolonoscopy, her last colonoscopy showed an approximately 1.3-1.5 cm polyp in the cecum and mild UC-like colitis in the ascending colon. Histology confirmed the presence of a moderately differentiated adenocarcinoma (T2N0M0) with loss of PSM2 expression at immunohistochemistry, in line with a hereditary nonpolypoid CRC associated origin. Laparoscopic subtotal colectomy with ileorectal anastomosis was offered as the treatment of choice, which revealed a 2.4 cm exophytic ulcerated lesion and pathology confirmed invasive moderately differentiated adenocarcinoma (pT2N0M0). Patient will remain on close endoscopic surveillance for the rectum. Our case highlights the importance of a strict endoscopic surveillance in patients with long-standing CD colitis, especially in patients with additional risk factors. The aim of this article was to highlight the importance of a strict endoscopic surveillance in CD in association with LS regarding a higher risk of CRC, which mandates the adaptation of the endoscopic surveillance intervals as well as the surgical approach and postoperative management/surveillance.