[A case of idiopathic hypereosinophilic syndrome with hepatic involvement in a 5-year-old boy].

Idiopathic hypereosinophilic syndrome is defined as the presence of prolonged eosinophilia without an identifiable underlying cause and with evidence of end-organ dysfunction. The organs involved are the heart, bone marrow, nervous system, lungs, liver, skin, and gastrointestinal tract. Hepatic involvement is found in about 30% of patients of idiopathic hypereosinophilic syndrome. It occurs rarely in infants and children. In this report, we experienced one case of idiopathic hypereosinophilic syndrome with hepatic involvement in a 5-year-old boy who complained of intermittent fever and right upper quadrant abdominal pain. An abdominal ultrasound examination revealed an ill-defined low-echoic lesion in the liver. Pathologic findings of a biopsy specimen clearly showed the infiltration of eosinophils in the liver. Laboratory data disclosed absolute eosinophilia. There was no evidence of allergic disease or parasitic infestation.