Hypereosinophilic syndrome presenting with inflammation in the retroparotid space and showing Villaret's syndrome

Hypereosinophilia syndrome (HES) is a rare disease characterized by the association between hypereosinophilia and eosinophil‐mediated organ infiltration and damage or dysfunction. The cause of hypereosinophilia is classified as neoplastic, reactive and idiopathic. However, hypereosinophilia causes tissue and organ damage, regardless of the underlying etiology. The common manifestations are pulmonary, skin and gastrointestinal. Rarely, neurological lesions are manifested. As neurological lesions of HES, mononeuritis multiplex, radiculopathy, optic neuritis, meningitis and cerebral infarction have been reported.