Pituitary gland and bone involvement of Langerhans cell histiocytosis in a boy and brief review of the literature.

A 3 years old boy was hospitalized with a month's history of polydipsia, polyuria and low fever. There was no relevant family history. This is a rare case of Langerhans cell histiocytosis (LCH) with both bone and pituitary infiltration shown on the technetium-99m methylene diphosphonate (99mTc-MDP) scan and brain magnetic resonance imaging (MRI). Sagittal and coronal T1-weighted images on MRI showed the typical lack of high signal intensity of the posterior pituitary which corresponded to the central signs of diabetes insipidus (DI). The diagnosis of LCH was suspected by 99mTc-MDP whole-body bone scan showing multiple bone lesions. The disease was further confirmed by pathology of the biopsy specimen from the right tibia. Brain MRI and bone scan are indicated for pediatric patients with DI. The high signal intensity of the posterior pituitary on MRI and the bone lytic lesions on scintigraphy suggested the diagnosis of LCH. This paper is original because it is the first full description of bone and pituitary involvement detected by bone scan and brain MRI in a pediatric LCH.