Hemorrhagic eosinophilic pericardial effusion associated with probable sparganosis

Sparganosis is a food-borne helminthic infection caused by the plerocercoid larvae of Spirometra species and is only rarely associated with serosal involvement. We report a 25-year-old man who presented with hemorrhagic eosinophilic pericardial effusion after ingesting undercooked frog meat. Peripheral eosinophilia, eosinophils in pericardial fluid, and markedly elevated immunoglobulin E raised suspicion for helminthic infection. Repeated cultures, cytology, cross-sectional imaging, cardiac magnetic resonance imaging, positron emission tomography/computed tomography, and next-generation sequencing did not identify an alternative cause. Serum enzyme-linked immunosorbent assay showed the strongest immunoglobulin G reactivity against Spirometra mansoni plerocercoid antigen. The patient was treated with pericardiocentesis, colchicine, indomethacin, and praziquantel, with subsequent normalization of eosinophilia and no recurrent pericardial effusion on follow-up echocardiography. This case adds to the limited literature on serosal sparganosis and highlights sparganosis as an uncommon but important cause of eosinophilic hemorrhagic pericardial effusion. Early recognition of this presentation may help avoid delayed diagnosis and unnecessary investigations.