Eosinophilia and endomyocardial fibrosis.

A 12 year old boy died after a 3 year course of recurrent and progressive heart failure. His cardiac symptoms began with a marked leukocytosis (white blood cell count 188,500/mm3) due to eosinophilia (90 percent). In 6 months, the leukocytosis and eosinophilia subsided, but the patient's heart failure progressed over the next 2 1/2 years. At autopsy there was no evidence of leukemia, but a severe endocardial fibrosis extending into the myocardium was found. The origin of endomyocardial fibrosis, although unknown, appears to have been related to the eosinophilia in this patient.