Abstract: Langerhans cell histiocytosis (LCH) is a rare neoplastic disease with abnormal proliferation of immature dendritic cells, and histopathological examination results is the "gold standard" for its diagnosis. The author reports a case of multisystem LCH in an adolescent with CT, MRI, and ¹⁸F-fluorodeoxyglucose(FDG) PET/CT imaging, and analyzes the characteristics of the disease from the clinical, histopathological, imaging, and therapeutic perspectives, and deepens the understanding of the disease by reviewing the literature to provide more references for the diagnosis of the disease.