Endocrine Abstracts

Introduction: Multisystem Langerhans cell histiocytosis (LCH) is a rare heterogeneous disorder caused by accumulation in multiple organs of dendritic cells phenotypically similar to cutaneous Langerhans cells. Pituitary involvement is present in about 25% of cases, and central diabetes insipidus is the most common deficit in that setting. Panhypopituitarism is rare, but hypothalamic-pituitary dysfunction is amongst the most frequent long-term complications of the disease.

Case report: We describe the case of a child with normal health status until the age of 7. He developed polyuria and polydipsia, was hospitalised and submitted to a water deprivation test, considered indicative of psychogenic polydipsia. At 14-years-old, elevated liver enzymes were attributed to EBV infection. Liver ultrasound showed hepatomegaly and heterogeneous echotexture. At 16-years-old, he presented with hypernatremia, delayed puberty and short stature, as well as slowly progressive dyspnea. Investigation revealed multiple pituitary deficits (hypogonadotrophic hypogonadism, secondary hypothyroidism, secondary adrenal insufficiency, growth hormone deficit) and central diabetes insipidus. Brain magnetic resonance imaging showed a hypothalamic mass (17 mm). He was started on hormonal replacement therapy (urofollitropin, human chorionic gonadotropin, levothyroxine, cortisone, desmopressin). LCH was suspected, and chest computed tomography revealed multiple cystic pulmonary lesions suggestive of the diagnosis, later confirmed by pulmonary biopsy. He started standard treatment with vinblastine and prednisone, with intermediate response after 6 weeks. He developed glucocorticoid-induced diabetes and needed multiple daily injections of insulin.

Conclusions: This case report illustrates the importance of investigating multiple signs and symptoms that arise in a multisystem and complex disorder. In this case, the endocrine consequences of LCH assume a central role. As was the case here, central diabetes insipidus can be the first manifestation of the disease, but its diagnosis is not always straightforward. Early diagnosis can prevent or delay permanent complications associated with multisystem disease; pituitary deficits, once established, are mostly permanent.