“Multifocal, intra-axial Langerhans cell histiocytosis presenting with central diabetes insipidus in teenage pregnancy: A case report”

Langerhans cell histiocytosis (LCH) is a rare disorder of clonal dendritic cells that can arise almost anywhere in the body and most commonly affects children under the age of 15. Lesions in the CNS can affect the hypothalamic pituitary region (HPR) and cause central diabetes insipidus (CDI), although isolated HPR involvement is extremely rare. We report the case of a 17-year-old G1P0 female at 22 weeks gestation presenting with new onset unilateral bell's palsy in the setting of longstanding CDI. She was subsequently found to have multifocal, intra-axial LCH throughout the HPR and brain parenchyma. This case highlights the importance of brain imaging with MRI over CT in the setting of pediatric patients presenting with isolated CDI. Prompt diagnosis of LCH can prevent spread throughout the CNS, including to the anterior pituitary gland, which could cause permanent hormone insufficiency.