Langerhans cell histiocytosis with central nervous system involvement: follow-up by FDG-PET during treatment with cladribine.

The prognosis of patients with Langerhans cell histiocytosis (LCH) involving the central nervous system (CNS) is generally poor, despite reports of clinical responses to chemotherapy, surgery, and radiation. We report on a patient with a 20-year history of relapsing multisystem LCH who developed progressive neuropsychiatric symptoms, including diplopia, ataxia, and mental deterioration. There was a regression of lesions in the brain stem and cerebellum following chemotherapy with cladribine (2-CdA) as evidenced by positron emission tomography (PET) scans. In conclusion, our experience is encouraging for the use of cladribine in CNS LCH. PET may be a useful modality for the monitoring of CNS disease activity in LCH and provides additional information in comparison with NMR imaging. (c) 2004 Wiley-Liss, Inc.