ANCA-negative eosinophilic granulomatosis with polyangitis (EGPA) manifesting as a large intracardiac thrombus and glomerulonephritis with angionecrosis.

A 59-year-old woman with a history of bronchial asthma presented with a prolonged fever and eosinophilia. There was transient proteinuria and troponin level was elevated. Antineutrophil cytoplasmic antibody was negative and she did not fulfil criteria for eosinophilic granulomatosis with polyangitis (EGPA). Echocardiography showed a large apical mass in the left ventricle, but there was no systolic dysfunction, local asynergy or ventricular remodelling. On MRI, apical mass was compatible with a thrombus and endocardial region was diffusely damaged. Loeffler endocarditis-like cardiac manifestation led to meticulous examination, which found no aetiology for eosinophilia. Finally, renal biopsy revealed eosinophil infiltration and glomerular angionecrosis, confirming as EGPA. This case highlights the isolated large cardiac thrombus as a rare presenting sign for EGPA and underscores current complicated strategy to diagnose EGPA. Of note, this clinical challenge was mostly caused by inchoate comprehension of hypereosinophilia-related disorders.