Case Report: Application of multimodal imaging in the diagnosis and treatment evaluation of primary cardiac lymphoma.

Primary cardiac lymphoma (PCL) is an extremely rare malignancy. This report describes a 76-year-old woman who presented with chest tightness, exertional dyspnea, and nocturnal orthopnea. Multimodal imaging (echocardiography, CT, CMR, PET) was central to the diagnostic process, enabling precise tumor localization, non-invasive tissue characterization, and disease staging, thereby raising strong suspicion for PCL. The diagnosis of primary cardiac diffuse large B-cell lymphoma (non-germinal center subtype) was subsequently confirmed by histopathology. The patient achieved complete remission after five cycles of chemotherapy, which was confirmed on 6-month follow-up imaging, with no recurrence over 65 months of surveillance. This case highlights that multimodal imaging provides complementary information crucial for the comprehensive evaluation of PCL, serving as a cornerstone for evidence-based clinical decision-making throughout the diagnostic and therapeutic continuum, from initial suspicion and staging to treatment response assessment.