Abstract
BACKGROUND: Cardiac T-cell lymphoma is a rare and aggressive malignancy that often presents with nonspecific symptoms and is difficult to diagnose early. CASE SUMMARY: A 73-year-old man presented with syncope, anorexia, and abdominal discomfort. During hospitalization, he developed hypereosinophilia and rapidly progressed to fulminant myocarditis. Despite steroid and immunoglobulin therapy, cardiac function declined, requiring extracorporeal membrane oxygenation and intra-aortic balloon pump support. Myocardial biopsy confirmed cardiac T-cell lymphoma with lymphocytic infiltration. DISCUSSION: Cardiac T-cell lymphoma with fulminant myocarditis is exceptionally rare and carries a poor prognosis. Diagnosis is often delayed because of vague symptoms. This case highlights the value of early myocardial biopsy and histopathologic evaluation in rapidly deteriorating cardiac function. TAKE-HOME MESSAGES: Early myocardial biopsy is crucial in cases of unexplained myocarditis with rapid deterioration. Cardiac T-cell lymphoma is a rare and aggressive condition that can rapidly progress to fulminant myocarditis in certain cases, necessitating early diagnosis and intervention.