29 year-old male with seizure and syncope. Intracerebral Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH), previously referred to as histiocytosis X, is a dendritic cell histiocytic tumor that demonstrates a variable spectrum of organ involvement. Clinical syndromes within this entity include eosinophilic granuloma, Hand-Schuller-Christian disease, Abt-Letterer-Siwe Disease, and Hashimoto-Pritzker disease. Currently, it is classified on the basis of extent, such as unifocal, multifocal, or disseminated disease.