Case Report SARS-CoV-2 Related Ischemic Colitis in an Adolescent With Trisomy 21: Diagnostic Pitfalls and Considerations Y Ma 1 , G Deutsch 2 , D Van Tassel 1,3,4 , M Shub 4,5 , S Schroeder 4,5,6 , J Krauss 7 , K Davenport 6,8,9 , and D Carpentieri 1,4,6,7 Abstract Millions of patients seek medical attention for diarrhea, vomiting, nausea, and abdominal pain. In the current environment, it is important to recognize that these symptoms may be the only manifestation or may precede more serious systemic complications of COVID-19. Herein, we describe the first case of ischemic colitis (IC) in a young adult who presented with diarrhea and highlight the laboratory pitfalls for patients with COVID-19 presenting with gastrointestinal (GI) symptoms. Keywords GI, immunohistochemistry, pediatric, COVID-19, surg path, microscopy Introduction Coronavirus are enveloped, nonsegmented, single- stranded, positive-sense RNA viruses named after their corona- or crown-like surface projections observed on electron microscopy corresponding to large surface spike proteins. 1 There are four distinct genera: Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus. SARS-CoV-2 is a recently described member of the Betacoronoravirus family (lin- eage B). There are six strains circulating across different geographical regions, all known to bind and fuse with angiotensin converting enzyme-2 (ACE-2) receptors. The ACE-2 receptors are expressed throughout the respiratory tract as well as the GI tract, hence the common pulmonary and less frequent GI manifesta- tions. 2,3 The GI pathogenesis is currently thought to be explained by activation of the spike proteins at the receptor sites, 4 immune evasion and potentially by alter- ations in the intestinal microbiome. 5 Case report This was a 17-year-old male with trisomy 21, status post patent ductus arteriosus closure and multiple ENT and eye surgeries. He was hospitalized at an outside institution with respiratory distress following six days of vomiting, diarrhea and abdominal pain treated with Azithromycin. Computed tomography (CT) suggested early appendicitis and airspace opacities. Ceftriaxone was prescribed and he was transferred to our institution for an appendectomy. His condition worsened within hours and a nasopharyngeal swab (NPS) for SARS- CoV-2 PCR was positive. His respiratory insufficiency improved with Dexamethasone and Remdesivir; howev- er, he developed worsening metabolic acidosis and dis- seminated intravascular coagulopathy (Figure 1). 1 School of Medicine, Creighton University, Phoenix, Arizona 2 Seattle Children’s Hospital, Seattle, Washington 3 Radiology Department, Phoenix Children’s Hospital, Phoenix, Arizona 4 The University of Arizona College of Medicine, Phoenix, Arizona 5 Gastroenterology Department, Phoenix Children’s Hospital, Phoenix, Arizona 6 Mayo Clinic, Phoenix, Arizona 7 Pathology Department, Phoenix Children’s Hospital, Phoenix, Arizona 8 Department of Surgery, Creighton University, Phoenix, Arizona 9 Surgery Department, Phoenix Children’s Hospital, Phoenix, Arizona Corresponding Author: D Carpentieri, Pathology Department, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA. Email: dcarpentieri@phoenixchildrens.com Pediatric and Developmental Pathology 2021, Vol. 24(5) 445–449 ! 2021, Society for Pediatric Pathology All rights reserved Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/10935266211015666 journals.sagepub.com/home/pdp