Abstract
Primary cardiac lymphoma (PCL) is very rare, and is extremely challenging to diagnose due to nonspecific symptoms. When discovered, the right atrium and ventricle are most commonly affected, while diffuse cardiac involvement is uncommon. PCL is fatal unless promptly diagnosed and treated. Herein, we present the case of a 36-year-old immunocompetent male who presented with a 5-year history of non-specific chest symptoms and was diagnosed with primary diffuse cardiac large B-cell lymphoma involving the entire heart.