[A case of idiopathic hypereosinophilic syndrome (HES) complicated by pulmonary infarction].

We experienced a case of idiopathic hypereosinophilic syndrome (HES) associated with pulmonary infarction. The case was a 22-year-old woman with marked eosinophilia (16835/microliters) and peripheral edema and cyanosis. During hospitalization, she suddenly developed lower right chest pain, and infiltrative lesions with pleural effusions in the right lung were prominent. A diagnosis of pulmonary infarction was made after perfusion scan and angiography of the lung. Lupus anticoagulant was found to be positive and a transient increase of anti-cardiolipin antibody slightly in her serum was also observed. Recurrent thrombosis is known to be complicated by HES but its mechanism remains to be clarified. There has also been no study reported in the literature on the role of lupus anticoagulant in this process; its possible role in this patient is discussed.