[Langerhans cell histiocytosis in the hypothalamus: a case report].

A case of Langerhans cell histiocytosis (LCH) in the hypothalamus is presented. A 52 year old man with eosinophilic granuloma of the lung was referred to our hospital. He complained of headache, easy fatigability, high fever, and voiding large quantities of urine, but was otherwise asymptomatic. T1-weighted images demonstrated a small mass in the hypothalamus. After about six months, the mass had grown to 2 cm in diameter. Surgery was performed by a pterional approach and a biopsy specimen was collected. Light microscopic examination of sections of the biopsy specimen showed polymorphous cellular infiltration by histiocytic cells, eosinophils, neutrophils, and lymphocytes. Electron microscopy showed Langerhans cells and Birbeck granules in the cytoplasm. The histological diagnosis was LCH, multifocal type. After low-dose radiation therapy, the mass gradually decreased in size. The clinicopathological features, neuroradiological findings, and treatment are briefly discussed.