Endocrine Abstracts

Introduction: Langerhans cell histiocytosis (LCH) is a rare disease that occurs mainly in childhood. In its multifocal form, the central nervous system may be affected, but rarely as the primary site of the disease. The prevalence of central diabetes insipidus (CDI) ranges from 10% to 50% and in most cases is established after the diagnosis of LCH. We report 2 cases of CDI that revealed a LCH.

Observations: Case 1: A one-year old male patient was admitted for polyuropolydypsic syndrome with a fever evolving in the long course. The water restriction test was positive with a positive response to Desmopressin. The diagnosis of CDI was retained. Hypothalamic-pituitary MRI showed thickening of the pituitary stalk. In addition, the child had hepatosplenomegaly and rash on clinical examination, cytolysis with hepatic cholestasis, and bicytopenia on biology.The liver biopsy showed sclerosing cholangitis with presence of histiocytic cells and positive PS 100. The BRAF mutation search is underway. The diagnosis of LCH in its multi-systemic form was retained. The patient was prescribed with Desmopressin substitution and underwent chemotherapy protocol with good progress. Case 2: A two-year old female patient was admitted for polyuropolydypsic syndrome evolving since 2 months. The examination on admission was without anomalies. The water restriction test was stopped after 8 hours because of a weight loss of 5% and a serum level of natremia of 146 mmol/l. The Minirin test was positive. The diagnosis of CDI was therefore retained. Cerebral MRI showed extensive enlargement and contrast enhancement of the pituitary stalk, absence of the spontaneous hypersignal of the post-pituitary and presence of an osteolytic lesion of the left occipital cranial vault. Bone scintigraphy showed bifocal bone involvement of the occiput and left scapula. The histological diagnosis of LCH has been confirmed. The child was prescribed with nasal Despopressine. The chemotherapy was not proposed in the absence of other locations.

Discussion: CDI may be the first manifestation even before LCH diagnosis. The endocrine system may be affected by LCH because Langerhans cells can migrate to the lymph nodes and affect the hypothalamic-pituitary axis. This can lead essentially to an irreversible CDI. CDI is more common in patients with BRAFV600E.