S4583 An Unusual and Difficult Colon Polyp in a Patient With Intestinal Schistosomiasis

Introduction: Schistosomiasis is caused by parasites (Schistosoma) found in freshwater snails. Humans may be infected when exposed to contaminated water. Schistosomiasis may cause gastrointestinal inflammation and may increase the risk of colorectal neoplasia. We report a pre-cancerous 10-millimeter colon polyp with an atypical endoscopic appearance growing on top of schistosomal eggs, which required a more involved polypectomy (endoscopic mucosal resection) than would be expected for a polyp of this size. Case Description/Methods: A 73-year-old woman with hypertension, hyperlipidemia, and history of advanced colonic polyp (prior tubular adenoma >1 centimeter) presented for surveillance colonoscopy without clinical symptoms. She had a history of schistosomiasis seen on polypectomy in prior colonoscopy which was treated with praziquantel. Physical exam and labs were unremarkable. Colonoscopy showed 1 10-millimeter polyp in the sigmoid colon with surrounding yellow-appearing mucosa that was unable to be removed with cold snare and required endoscopic mucosal resection. There was also abnormal mucosa with a yellow hue in the recto-sigmoid colon. Polypectomy pathology revealed tubular adenoma with Schistosoma eggs, and rectosigmoid mucosa biopsies noted Schistosoma eggs. Discussion: Intestinal schistosomiasis can be caused by Schistosoma mansoni, japonicum, intercalatum, guineensis, and mekongi. Gastrointestinal manifestations include diarrhea, constipation, abdominal pain, and loss of appetite. Endoscopic findings may include yellow nodules, polyps, or ulcers. Biopsy of intestinal tract mucosa may demonstrate characteristic granulomas surrounding eggs embedded in the mucosa. Inflammation caused by colonic schistosomiasis, particularly Schistosoma japonicum, has been implicated as a risk factor for colorectal neoplasia, however, the relationship is unclear. In this case, we captured a polyp growing on top of a focus schistosomiasis eggs, highlighting this potential relationship. Furthermore, the polyp was unexpectedly difficult to remove, which may be related to the underlying distortion of the colon from schistosomiasis. Gastroenterologists should be aware of the potential relationship between schistosomiasis and colorectal neoplasia and appreciate that polyps with this endoscopic appearance and/or in this clinical background may require more involved polypectomy due to underlying inflammation or fibrosis resulting from schistosomiasis.