A 76-year-old male with a known history of diabetes mellitus, ischemic heart disease, and chronic heart failure presented to the internal medicine department with progressively worsening shortness of breath and a significant decline in hemoglobin levels.

On initial assessment, the patient appeared dyspneic. Cardiac evaluation revealed moderately reduced left ventricular systolic function, with an estimated ejection fraction of 40%. Regional wall motion abnormalities were noted, including akinesia of the apical septal and apical segments. Additionally, imaging demonstrated a large pericardial effusion.

Electrocardiography showed normal sinus rhythm with low-voltage QRS complexes. Chest X-ray revealed a markedly enlarged cardiomediastinal silhouette, along with progression of bilateral mid- and lower-zone ground-glass opacities and increased interstitial markings, suggestive of pulmonary edema. Blunting of both costophrenic angles was observed, more pronounced on the right side, consistent with pleural effusion.

Laboratory investigations demonstrated a hemoglobin level of 9.6 g/dL, leukocytosis with a white blood cell count of 13.4 × 10⁹/L, and thrombocytosis with a platelet count of 398 × 10⁹/L. Iron studies confirmed significant iron deficiency, with a serum iron level of 2 µmol/L and ferritin of 18.5 ng/mL.

Given the presence of a large pericardial effusion and associated clinical symptoms, the patient underwent echo-guided pericardiocentesis via a subxiphoid approach. A total of 1250 mL of pericardial fluid was successfully aspirated, resulting in marked clinical improvement.

Cytological analysis of the pericardial fluid revealed large cells arranged in cohesive clusters, consistent with an inflammatory process. Polymerase chain reaction (PCR) testing for Mycobacterium tuberculosis was negative.