Case Presentation: A 60-year-old man with a history of peptic ulcer disease presented to the emergency room with a two-month history of sharp right lower quadrant abdominal pain that worsened with oral intake, nausea, vomiting, an unintentional 25-pound weight loss, and occasional hematochezia. He denied regular NSAID use, melena, early satiety, heartburn, odynophagia, or dysphagia. Gastroenterology was consulted for evaluation of these symptoms in the context of acute microcytic anemia, with a decrease in hemoglobin from 10 to 8 g/dL over one month. Further lab findings included elevated erythrocyte sedimentation rate at 48 mm/hr, elevated C-reactive protein level at 14.4 mg/L, carcinoembryonic antigen level of 5.2 ng/mL, and negative H. pylori stool antigen. A CT abdomen/pelvis (CTAP) suggested an intraluminal hematoma of the ascending colon near the ileocecal junction versus an underlying colonic mass. A 3-phase CTAP performed 3 hours later delineated an ileocolic intussusception. Due to the high risk of intestinal perforation, colonoscopy was deferred, and the patient underwent emergency exploratory surgery during which a large, palpable cecal mass and ileocolic intussusception were found. A right hemicolectomy with ileocolic anastomosis was performed. Histologic examination (Figure 1) revealed a pT3pN0 invasive mucinous adenocarcinoma of the colon (MAC). The patient was eventually discharged with an outpatient Oncology referral.
Discussion: Colonic intussusception is rare in adults and represents only 5% of all intussusception cases in this patient population [1]. Symptoms commonly include intermittent abdominal pain, nausea, and vomiting. The classic constellation of abdominal pain, vomiting, currant-jelly stools, and a palpable abdominal mass characterizing many pediatric intussusception cases is rare in adults [2]. Acute intussusception with a background of unintentional weight loss in an adult should elicit suspicion of underlying malignancy, as the medical literature suggests up to 66% of colonic intussusception cases are secondary to malignancy [3,4]. Most cases involve primary colonic adenocarcinomas, though metastatic cancers and lymphomas have also been reported [3,4]. In children, 90% of intussusception cases occur in the ileocolic region. In adults, the location of intussusception varies considerably. MAC most commonly presents in the right hemicolon, accounts for 10-15% of all colorectal cancer cases, is more common in young women, and is usually diagnosed at advanced stages [5]. It has a poor prognosis and may be less responsive to traditional chemotherapies when compared to other subtypes of colorectal adenocarcinoma [5]. Colon cancer may initially present with intussusception before other clinical manifestations develop. Thus, this patient’s surgical emergency may have had a silver lining – that is, accelerated diagnosis at an earlier stage.
Conclusions: Intussusception in an elderly adult should never be taken lightly. Further investigation into the underlying cause of the intussusception is necessary as malignancy is a common etiology in adult patients. With colon cancer on the rise in the general population, initial presentations of colon cancer with acute intussusception in the hospital setting will likely rise in proportion. Early consultation and involvement of Gastroenterology and General Surgery is recommended to uncover the truth “behind the twist.”
