A case of hypereosinophilic syndrome with asymmetric septal hypertrophy.

A case of idiopathic hypereosinophilic syndrome (HES) with asymmetric septal hypertrophy (ASH) is described: this is a very rare association. The patient was a 56-year-old male with hypereosinophilia lasting for 10 years. The white blood cell count was 11200/mm3, with 22% eosinophils, and eosinophilic hyperplasia (7.2%) was noted in the bone marrow. A peripheral blood smear showed vacuolated eosinophils with a reduced content of granules. An ultrastructure study of the eosinophils revealed reduced numbers of crystalloid granules which appeared to be dissolving with reversal of normal staining. An echocardiogram and a biventriculoglam indicated ASH with the interventricular septal wall thickness of 2.4 cm and the left ventricular posterior wall thickness of 1.5 cm. Right ventricular endomyocardial biopsy revealed no eosinophilic infiltration, but endocardial thickening, subendocardial fibrosis, hypertrophy, myocytolysis, and fragmentation of muscle bundles were observed.