Neurodegeneration in histiocytoses might start in utero

Histiocytic disorders, such as Langerhans cell histiocytosis and Erdheim-Chester disease, are characterised by inflammation and accumulation of cells derived from the monocyte and macrophage lineages, resulting in tissue damage. Neurodegenerative lesions in Langerhans cell histiocytosis are a devastating type of CNS involvement—different from tumour infiltration—in which patients present with progressive symmetric cerebellar syndrome, tetrapyramidal syndrome with or without motor deficits, pseudobulbar palsy, or cognitive impairment.