S3846 A Rare Case of Right-Sided Colon Cancer With Invasion of the Duodenum

Introduction: We present a unique case of right-sided colon cancer invading into the duodenum. Case Description/Methods: A 48-year-old man from Honduras with no medical history presented with abdominal pain, nausea, vomiting and 50 lbs weight loss for 4 weeks. He was initially febrile, tachycardic, tachypneic; labs with anemia, leukocytosis, positive polymicrobial blood cultures and elevated lactate. CTAP showed 10 cm in length circumferential wall thickening involving colonic hepatic flexure associated with duodenal wall thickening and duodenal inflammation with possible fistula. Repeat CTAP showed increased size multiloculated mass in the right hepatic lobe extending to the right and inferior liver and measuring 9.3 × 8.3 × 10.3 cm. Gastroenterology team performed an EGD which revealed a duodenal mass likely eroding from the colon and a colonoscopy which showed an obstructing mass in the ascending colon highly suggestive of malignancy and subsequent biopsy of the mass was performed. CEA later found to be elevated to 6.8. Liver and colonic mass pathology results showed invasive and in-situ moderately differentiated adenocarcinoma of the ascending colon associated with necrosis; fragments of adenocarcinoma of the duodenum associated with necrosis consistent with cT4 Nx M0 disease. No evidence of malignancy in the liver tissue was found. The patient underwent en bloc right hemicolectomy, lymphadenectomy and right Whipple procedure by surgical team. Discussion: Right-sided colon cancers (RSCCs) typically originate in the ascending colon, and are frequently detected at a more advanced stage. An estimated 5.5-16.7% of colorectal cancers present as locally advanced tumors that invade adjacent organs. The incidence of RSCCs invading adjacent structures like the duodenum or the pancreas ranges from 11-28%. A concerning pattern of progression in RSCCs involves direct tumor invasion into the duodenum. Management of CRC generally includes a combination of surgical resection, chemotherapy, radiotherapy, molecular targeted therapy, and immunotherapy. When only the duodenum is involved, the treatment of choice is right hemicolectomy (RH) en bloc. If the tumor has also invaded the pancreas, a more extensive procedure is required, consisting of a right hemicolectomy (RH) en bloc with duodenopancreatectomy (DP), referred to as the Whipple procedure. Our patient underwent RH en bloc, lymphadenectomy and right pancreaticoduodenectomy (Whipple procedure).