Case ReportsPerforated appendicitis induced by pembrolizumab: a case report and review of the literaturePapageorgiou, Georgios I.a; Fergadis, Evangelosa; Skouteris, Nikosa; Christakos, Evridikia; Tsakatikas, Sergios A.a; Filippakou, Aikaterinib; Papantoni, Evangeliac; Stanc, Gabrielad; Souka, Efthymiad; Valavanis, Christosd,e; Kosmas, ChristosaAuthor Information aDivision of Medical Oncology and Hematopoietic Cell Transplant Unit, Department of Medicine bDepartment of Gastroenterology cDepartment of Surgery dPathology Department eMolecular Pathology Unit, ‘Metaxa’ Cancer Hospital, Piraeus, Greece Received 19 August 2021 Revised form accepted 19 August 2021 Correspondence to Georgios I. Papageorgiou, MD, Division of Medical Oncology and Hematopoietic Cell Transplant Unit, Department of Medicine, ‘Metaxa’ Cancer Hospital, 51 Botassi Street, 18537 Piraeus, Greece, Tel: +306940068547; e-mail: [email protected] Anti-Cancer Drugs: February 2022 - Volume 33 - Issue 2 - p 208-213 doi: 10.1097/CAD.0000000000001247 Buy Metrics Abstract Monoclonal antibodies against programmed cell death protein 1 (PD-1) and PD-1 ligand 1 (PD-L1) are the main representatives in the field of immunotherapy and their indications are constantly increasing in medical oncology and hematology during the last decade. They are associated with long-lasting responses and an acceptable toxicity profile, although they may infrequently cause life-threatening complications requiring prolonged hospitalization or urgent interventions. With the current report, we present the case of a 75-year-old woman diagnosed with stage IV lung adenocarcinoma, who developed acute abdominal pain without preceding symptomatology while on pembrolizumab-pemetrexed maintenance treatment. A contained rupture of the appendix was found, for which she was managed conservatively. Subsequent endoscopic as well as histopathological findings from biopsies obtained via colonoscopy associated the clinical and imaging findings with grade 4 immune-mediated colitis. Interestingly, high-grade colitis is more frequent with anti-CTLA-4 agents in comparison to anti-PD-1 agents; moreover, most cases of anti-PD-1-mediated colitis present with preceding symptomatology (like diarrhea or vomiting), while cases or colonic perforation are extremely rare if ever described. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.