Adult-Onset Langerhans Cell Histiocytosis with Central Nervous System Neurodegeneration and Neuropsychiatric Symptoms: A Case Report with Novel Imaging and Genetic Insights

Langerhans cell histiocytosis (LCH) is a rare multisystemic clonal proliferative disorder, that typically affects children. Central nervous system involvement, especially in adults, is exceptionally uncommon and diagnostically challenging. We report the case of a 55-year-old woman who presented with persistent generalised itching, scalp lesions, noduloulcerative lesions, and behavioural changes. Imaging showed findings suggestive of neurodegenerative LCH. Hormonal studies showed anterior pituitary dysfunction, notably without symptoms of diabetes insipidus. Histopathology confirmed LCH and molecular testing identified B-Raf protooncogene serine /threonine protein kinase (BRAF) V600E mutation. The patient did not adhere to immunosuppressive treatment and ultimately succumbed. This case highlights the diagnostic complexity of neurodegenerative adult-onset LCH and emphasises the importance of early suspicion, novel imaging interpretation, molecular diagnostics, and patient adherence to therapy.