Central diabetes insipidus as presenting symptom of Langerhans cell histiocytosis

BACKGROUND AND OBJECTIVES: Central diabetes insipidus (CDI) is a rare disorder associated with various underlying diseases. Among the systemic diseases that may cause CDI, Langerhans cell histiocytosis (LCH) is the most common. Therefore, in patients with endocrinologically proven CDI, a comprehensive diagnostic evaluation is crucial to identify possible extracranial sites of LCH. The goal of the diagnostic evaluation is to yield histopathological proof of the underlying disease. If possible, this histopathological proof should be provided by a biopsy of extracranial lesions to avoid a potentially hazardous biopsy of the pituitary stalk. STUDY DESIGN: In this retrospective study we included 54 patients registered at the LCH study reference center in whom the onset of CDI preceded the diagnosis of LCH, and we investigated their presentation and course to define a clinical pattern characteristic for LCH. RESULTS: In 49/54 patients (91%) the detection and biopsy of extracranial lesions led to the diagnosis of LCH. The most frequently involved organs were bones, skin, and lungs; 86% of the patients with bone lesions had skull lesions. In 18% of the patients extracranial lesions were already found at presentation of CDI, in another 51% of the patients extracranial lesions were found within 1 year from onset of CDI. CONCLUSIONS: These observations underline that a comprehensive search for extracranial lesions at presentation and during the first year thereafter may help to achieve a specific diagnosis without a pituitary stalk biopsy.