Abstract
OBJECTIVES: Primary cardiac lymphoma represents an extremely rare entity of extranodal non-Hodgkin lymphoma. CASE PRESENTATION: We report the case of a woman who presented with dyspnea, asthenia, chest pain, cough, and odynophagia. Investigations revealed a diffuse large B-cell lymphomas type primary cardiac lymphoma through cytological examination of pericardial fluid. Confirmatory diagnosis was established through cytology of pericardial effusion, supported by imaging techniques. The patient completed all cycles of chemotherapy and is currently in remission. CONCLUSIONS: This case highlights the essential role of accurate cytological evaluation by laboratory professionals, which can facilitate early diagnosis and may obviate the need for more invasive procedures such as endomyocardial biopsy.