Langerhans Cell Histiocytosis Involving the Hypothalamic–Pituitary System Accompanied by Adipsic Diabetes Insipidus and Multiple Anterior Pituitary Hormone Deficiencies: A Case Report

Adult-onset Langerhans cell histiocytosis (LCH) is an uncommon disease. Central nervous system involvement, particularly of the hypothalamic–pituitary complex, can provoke severe endocrine and neurological complications. We report the case of a 39-year-old female patient with a history of pulmonary LCH who developed central diabetes insipidus (CDI), anterior pituitary dysfunction, and severe hypothalamic syndrome, accompanied by adipsia, thermoregulatory dysfunction, and cognitive impairment. Brain magnetic resonance imaging revealed a hypothalamic mass with peritumoral edema. Following ineffective corticosteroid therapy, cladribine was administered. Although the tumor size and edema significantly decreased, it caused prolonged grade 4 bone marrow suppression, necessitating treatment discontinuation. Despite the marked radiological improvement, multiple anterior pituitary hormone deficiencies, cognitive impairment, and irreversible hypothalamic dysfunction persisted. Furthermore, concomitant adipsic CDI and thermoregulatory failure provoked severe dehydration, complicating clinical management. Ultimately, the patient died of sudden cardiac arrest, secondary to extreme hypernatremia (170 mEq/L) and dehydration-induced cardiopulmonary collapse. The case presented herein highlights the possible devastating consequences of hypothalamic involvement in adult multisystem LCH. While cladribine is effective at reducing the tumor burden, it fails to reverse established neuroendocrine and neurodegenerative damage. Early therapeutic and further lifelong interventions, specifically for adipsic CDI, are crucial to preventing fatal outcomes and maintaining quality of life.