Langerhans cell histiocytosis with central nervous system involvement--complete response to 2-chlorodeoxyadenosine after failure of tyrosine kinase inhibitor therapies with sorafenib and imatinib.

Langerhans cell histiocytosis (LCH) is rare in adults, and only a subset of these patients suffers from central nervous system (CNS) involvement. Hence, evidence-based treatment recommendations are lacking. A case of a 20-year-old student with multisystem LCH and extensive CNS involvement is described, who showed a durable response to 2-chlorodeoxyadenosine after prior therapies with the tyrosine kinase inhibitors sorafenib and imatinib. In accordance to the experiences provided by other case series, which are reviewed herein, 2-chlorodeoxyadenosine can be considered an effective and safe option for adult LCH with CNS involvement.