ABSTRACT
A 21-year-old male was hospitalized for recurrent swelling of lower limbs (lymphedema) for 1 year and worsening of it for 1 week.Physical examination revealed several smooth,firm enlarged lymph nodes of the neck,groin without apparent tenderness measuring about 1 cm in diameter.Cardiac and pulmonary auscultation showed no obvious abnormality.The abdomen was soft on palpation without tenderness or rebound tenderness.Skin examination revealed swelling of both lower limbs,especially the left lower limb,as well as scattered irregularly sized,dark erythematous patches with a wood-like consistency on the swollen lower limbs,with high temperature but no tenderness.Elevated peripheral eosinophil count was observed before and after admission,with the eosinophil percentage higher than 70％.Vascular ultrasonography showed thrombosis in the right anterior tibial artery,left dorsal artery of foot and lower portion of the left great saphenous vein.Multiple enlarged lymph nodes were found by computed tomography in the mediastinal,bilateral axillary,retroperitoneal regions and around the abdominal aorta.Lymph node and bone marrow biopsies showed eosinophilia.Histopathology of lesions on the extensor aspect of the left medial thigh and left lateral malleolus showed massive eosinophilic infiltration and lymphatic dilation in the dermis,as well as eosinophil emboli in some lumens.The FIP1L1-PDGFRA fusion gene was undetected.A diagnosis of idiopathic hypereosinophilic syndrome was finally made.The symptoms rapidly regressed after glucocorticoid treatment.