eP400 - Case Presentation of Immunotherapy Mediated Severe CMV Colitis Requiring Total Abdominal Colectomy with End Ileostomy

Purpose/Background: CMV colitis most commonly occurs in immunocompromised patients with acquired immunodeficiency syndrome (AIDS), organ transplantation, hematological malignancy, cancer therapy and corticosteroid use1. The role of CMV in inflammatory bowel disease is controversial. It is unknown if CMV is the cause of exacerbation of the disease, reactivation if a consequence of disease, or its presence is a confounder1. The diagnosis is typically established with colonic tissue biopsy taken at the ulcer edge or base. Avelumab (Bavencio) is a monoclonal antibody for PD-L1 receptor and FDA approved for indication in the treatment of Merkel cell carcinoma, urothelial carcinoma and renal cell carcinoma. CMV colitis has been reported as a rare side effect of Avelumab (1.5 %, 26/1738). We are presenting a rare case of immunotherapy mediated CMV colitis refractory to corticosteroids requiring a total abdominal colectomy with end ileostomy.Methods/Interventions: 66 YO M w/ PMHx of stage 4 bladder cancer on Avelumab, diverticulitis, PE, prior C diff colitis presented with 20 episodes of bloody bowel movements daily. Prior C diff was treated with oral vancomycin which was then switched to Dificid due to worsening diarrhea. Patient was readmitted few months later with continuing diarrhea. Stool cultures were positive for Strongyloides which was treated with 2 days of ivermectin and prednisone. Patient continued to take Dificid during this time, repeat sigmoidoscopy was performed showing severe colitis with a presumptive diagnosis of immunotherapy mediated colitis. Biopsy showed acute inflammation with mucosal erosion, no granulomas, negative for CMV, vitals signs stable. WBC was elevated at 17,500. Physical exam was a soft abdomen, tender to palpation in the left lower quadrant, nondistended. Imaging was significant a CT Abdomen/Pelvis w/ IV contrast showed diffuse mural thickening and submuscosal edema with pericolonic inflammation in descending, sigmoid and rectum. After failing medical treatment patient was taken to the operating room for Total abdominal colectomy with end ileostomy.Results/Outcomes: Final pathology resulted with significant colitis, ulceration with crypt abscesses and pseudopolyps, no granulomas. Positive for CMV cells on immunostaining, favoring a diagnosis of CMV ColitisConclusion/

Discussion: CMV colitis is a challenging diagnosis to make and in our case was initially negative, but on final pathology stained positive. The treatment algorithm currently includes treatment with ganciclovir which is often poorly tolerated due to its severe side effect profile. CMV should be treated when histologic mucosal examination reveals high grade CMV density, low grade CMV density who have corticosteroid refractory disease, or endoscopically large ulcer1. The treatment of steroid refractory colitis requires close interdisciplinary discussions with medical oncologists, gastroenterologists and colorectal surgeons for the optimal treatment pathways.