2543 Duodenal Traditional Serrated Adenoma (TSA) Presenting as Small Bowel Intussusception

Abstract

INTRODUCTION: Intestinal intussusception is the telescoping of a proximal into an adjacent distal segment of the gastrointestinal (GI) tract. Intussusception is rare in adults, accounting for less than 5% of all mechanical bowel obstructions. Approximately 80-90% of intussusceptions in adults are secondary to an underlying pathological process, including malignant lesions, polyps, or Meckel's diverticulum. Therefore, when intussusception occurs in adults, further investigation to determine the etiology is warranted. CASE DESCRIPTION/METHODS: A 48 year-old female without significant past medical history developed severe, episodic abdominal pain six to eight weeks prior to presentation with associated nausea and occasional emesis. Recent CT scan of the abdomen and pelvis with contrast demonstrated small bowel intussusception in the area of the ligament of Treitz (Figure 1). Laboratory investigations were notable for microcytic anemia. She was referred to gastroenterology and underwent extended esophagogastroduodenoscopy (EGD) which revealed a 4 cm mass in the fourth portion of the duodenum (Figure 2). Initial mucosal biopsy suggested a possible tubulovillous adenoma with low-grade dysplasia. She subsequently underwent surgical resection of the small bowel mass with duodeno-jejunostomy. Surgical pathology revealed a traditional serrated adenoma (TSA) with low-grade dysplasia forming a cluster of polyps ranging from 0.5 to 4.3 cm in size (Figure 3). She did well postoperatively and was discharged on post-operative day 6. She will be undergoing colonoscopy after recovering from surgical intervention. DISCUSSION: Of the three types of serrated adenomas, TSA is the least common, accounting for only 5% of serrated polyps. These are commonly found in the colorectum and have rarely been described in other portions of the GI tract. The first case of TSA of the duodenum was not described until 2004. More recently, TSAs have been detected throughout the upper GI tract. However, reports of TSAs causing small bowel intussusception have not been described. This novel case highlights the importance of considering this in the differential for any adult with proximal small bowel intussusception. Importantly, TSAs of the upper GI tract may represent more aggressive lesions with high malignant potential and should be excised to rule out the possibility of a developing malignancy.