Case of the Month - September 2020 Case of the Month Archive A 44 year-old man with history of Crohn’s disease presented for a routine follow-up colonoscopy. He was in remission on adalimumab (Humira) injections every two weeks for the past three years. There was no recent history of weight loss, abdominal pain, bloating, or diarrhea. The patient’s medical history was otherwise significant for diabetes mellitus, hypertension, and a laparoscopic jejunal resection three years ago. He is a current smoker. During colonoscopy, ulcerations were seen on the left side of the colon and rectum, and worms were found throughout all segments of the colon, including at the appendiceal orifice. Several biopsies were taken and histopathologic examination showed mild inflammation and ulceration in the colon and fragments of micro-organisms separate from the mucosa. What is your diagnosis? Figure 1: photograph taken during colonoscopy, with an arrow indicating the worm seen in the ascending colon. Figure 2: histology sections with H&E stains showing a cross-section of the worm with black arrow indicating the prominent lateral alae, red arrow indicating the thick cuticle and the blue arrow showing the musculature (A) and a fragment of a gravid female helminth with eggs that are oval-shaped and flattened on one side (B).