SARS-CoV-2-Related Multisystem Inflammatory Syndrome in an Immunocompromised Child with Osteosarcoma Revealed by Hepatocellular Failure

Introduction: Multisystem Inflammatory Syndrome in Children (MIS-C) is a new phenomenon reported worldwide with temporal association with COVID-19. Objective: The aim of our case report is to clarify the manifestations of a pims syndrome in a osteosarcoma field, which can be confused with metastases. Patients and methods: We report a case of a 12-year-old male patient followed for osteosarcoma of the right humerus who was admitted for hepatocellular failure with cutaneous-mucosal jaundice revealing a PIMS syndrome. Results: The patient had initially received 3 courses of chemotherapy, followed by monobloc resection of the tumour mass and osteosynthesis, who met the case definition of PIMS-TS presented with fever, multi organ and mucocutaneous involvement, cardiovascular and gastrointestinal symptoms. His biological work-up showed a significant inflammatory syndrome with very high ferritin levels, high D-dimer and pro-BNP levels, associated with lymphopenia and liver cytolysis. An echocardiogram revealed a dilated cardiomyopathy with an LVEF of 13% associated with a moderate pericardial effusion. The work-up was completed by a PCR covid which came back negative, when the serology came back positive confirming a PIMS-TS. Therapeutically, he received a course of immunoglobulin, corticosteroid, and in view of the myocardial damage, he was put on Aspirin, ACE inhibitor, beta-blocker and spironolactone after normalization of his blood pressure. The evolution was spectacular, marked by a clear clinical improvement, the normalisation of biological parameters and the improvement of his LVEF on echocardiography. Conclusion: Although the pathogenesis is not clearly known, immune-mediated injury has been implicated. We herein provide current information on this condition, in order to raise awareness amongst pediatricians.