A 63-year-old woman was hospitalized after 2 episodes of mucoid, maroon-colored stools. She denied any prior or current episodes of abdominal pain, vomiting, fever, or recent travel. She was hemodynamically stable without significant drop in hematocrit. Colonoscopy revealed a 5-cm polypoid mass in the ascending colon with ulceration and fat eroding through the mucosa (Figure 1). The colonicsegment proximal to the mass could not be visualized on colonoscopy, but abdominal computed tomography (CT) showed a 5 x 3 x 4-cm fat density mass at the hepatic flexure causing colocolic intussusception of the ascending colon into the proximal transverse colon.
Figure 1. Colonoscopy showing a 5-cm polypoid mass in the ascending colon with ulceration and fat eroding through the mucosa.
Axial CT demonstrated the classical “target” sign and coronal view demonstrated a “sausage-shaped” mass (Figure 2). Initially, the patient refused surgical intervention but subsequently agreed, as she had recurrent rectal bleeding. On laparotomy, the ascending colonic segment was found gangrenous; therefore, a right hemicolectomy with ileocolic anastomosis was performed. Histolopathology confirmed a benign submucosal lipoma (Figure 3) and normal lymph nodes. Postoperatively the patient recovered well.
Figure 2. (A) Axial view abdominal CT showing classical target sign (arrow) of intussusception. (B) Coronal view abdominal CT showing a sausage-shaped mass (arrow) caused by colo-colic intussusception.
Intussusception is a process in which a segment of intestine invaginates into the adjoining intestinal lumen, causing bowel obstruction. It is usually a pediatric condition, and less than 5% cases of intussusceptions are reported in adults.1 Unlike the classical triad of abdominal pain, mass, and bloody diarrhea seen in children, adult presentation is often atypical, as in our case, with only painless rectal bleeding. Abdominal CT is the preferred imaging modality. An underlying pathological lesion acts as a “lead point” in 90% cases of adult intussusception. In case of colo-colic intussusception, over 50% of times the lead point is found to be a malignancy.2 Rare cases of colonoscopy-induced intussusception have been reported, which may be a precipitating factor in our patient as well.3 Although the majority of colonic lipomas are small and asymptomatic, giant ones (>4 cm) can present with intussusception, often requiring surgery.4 Given the high probability of an underlying malignant process, surgical resection of the involved bowel segment was often recommended to avoid seeding. Recently, there is growing evidence disputing this practice and favoring non-operative reduction when feasible, particularly for small intestinal intussusception with benign etiology.1,2 Due to its rarity and nonspecific presentation, clinical diagnosis of intussusception in adults is challenging. Giant colonic lipoma could serve as a lead point.
Figure 3. Histopathological image (20x magnification, H&E stain) of the mass showing a well-circumscribed submucosal lipoma.
Author contributions: Both authors collected data and wrote the manuscript. A. Kumar is the article guarantor.
Financial disclosure: None to report.
Informed consent was obtained for this case report.
Acknowledgements: The authors thank Dipti Sagar, MD, for providing colonoscopic images.
Correspondence: Anand Kumar, Montefiore Medical Center, Department of Medicine/Division of Hospital Medicine, 11 East 210th St, Bronx, NY 10467 (email@example.com).
Received January 9, 2016; Accepted Feburary 24, 2016
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