Myxoid Pleomorphic Liposarcoma Imitating Recurrent Traumatic Hemopericardium

Primary pericardial malignancies are rare, and myxoid tumors may mimic hemorrhagic pericardial effusions on imaging, leading to diagnostic delay.

A 56-year-old man presented with pleuritic chest pain and was diagnosed with acute pericarditis and a presumed traumatic hemorrhagic pericardial effusion. Despite anti-inflammatory therapy and pericardiocentesis yielding bloody, lymphocyte-predominant fluid with negative cytology, he experienced rapid clinical deterioration. Repeat imaging revealed an encasing pericardial mass causing severe left atrial compression and functional mitral stenosis. Emergent surgical exploration identified a large solid pericardial tumor. Histopathology confirmed primary myxoid pleomorphic liposarcoma. The patient underwent surgical resection followed by adjuvant chemotherapy and radiotherapy.

This case highlights the myxoid tumor's masquerade as a hemorrhagic effusion, the limitations of pericardial fluid cytology for sarcoma, and the hemodynamic consequences of external cardiac compression.

Persistent or recurrent bloody pericardial effusions with atypical imaging features warrant suspicion for malignancy despite negative cytology.