Eosinophilic granulomatosis with polyangiitis presenting with eosinophilic myocarditis as the only organ involvement.

Unlabelled: A 45-year-old man with a history of bronchial asthma had fever and elevated eosinophils on the day of surgery for sinusitis, resulting in cancellation of the surgery. Two days later, he was referred to our department for electrocardiographic abnormalities. We suspected eosinophilic myocarditis (EM) since he presented with fever, left ventricular hypokinesis, and hypertrophy on echocardiography, and eosinophilia with elevated cardiac enzymes. We immediately performed an endomyocardial biopsy that showed eosinophilic infiltration of the myocardium. He was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA) since he suffered from asthma, eosinophilia, sinusitis, and EM. Methylprednisolone pulse therapy followed by oral prednisolone and intravenous cyclophosphamide pulse therapy decreased his eosinophils to within the normal range, and his symptoms subsequently improved. In EGPA, cardiac involvement is less commonly seen compared to other organ involvement. Moreover, patients with EGPA who have cardiac involvement generally have other organ involvement as well. In this report, the patient had only cardiac involvement as organ damage associated with EGPA, except for asthma and sinusitis in the prodromal phase, making it clear that patients with EGPA could present with cardiac involvement alone. Therefore, it is recommended to thoroughly examine for cardiac involvement in patients with suspected EGPA.

Learning Objective: We report a case of eosinophilic granulomatosis with polyangiitis (EGPA) presenting with cardiac involvement alone as organ damage, subsequently diagnosed with eosinophilic myocarditis as confirmed by an endomyocardial biopsy. EGPA usually involves other organs in addition to the cardiovascular system; however, patients with EGPA could present with cardiac involvement alone, as in this case. Thus, we should thoroughly investigate for cardiac involvement in patients with suspected EGPA.