Recurrent Myocarditis After COVID Vaccination in a Patient With FLNC Mutation Undergoing Treatment for Lymphoma

BACKGROUND: Filamin C (FLNC) variants are often associated with structural cardiomyopathies but rarely myocarditis. CASE SUMMARY: A 60-year-old man with newly diagnosed B-cell lymphoma and initiation of cancer therapy presented with substernal chest pain. He had experienced myocarditis 2 years ago from a COVID-19 vaccine or possible infection; however, he received another COVID-19 booster in anticipation of upcoming cancer therapy. He was diagnosed with acute myocarditis, and his course was complicated by cardiac arrest requiring multidisciplinary management. Outpatient genetic testing revealed a pathogenic FLNC variant. DISCUSSION: This report highlights the case of a patient with FLNC mutation who developed recurrent myocarditis in the setting of exogenous factors, including the COVID-19 vaccine and a history of lymphoma and immunotherapy. TAKE-HOME MESSAGES: Myocarditis may be the initial presentation for certain genetic cardiomyopathies. Genetic testing should be strongly considered in patients with multiple episodes of myocarditis.