Successful treatment of adult Langerhans cell histiocytosis with intensified chemotherapy.

Langerhans cell histiocytosis (LCH) is a rare disease in adults. The treatment strategy for this condition remains controversial. Intensified systemic chemotherapy is required in pediatric patients with the multiple system form of LCH (MS-LCH) for aggressive forms of the disease. Recent clinical trials have shown that intensified chemotherapy for pediatric patients diagnosed with MS-LCH results in improved outcomes. However, whether the feasibility and efficacy of an intensified systemic chemotherapy regimen are also beneficial for adult patients with MS-LCH remains unclear. Here, we report two cases of adult MS-LCH that were successfully treated with an intensified treatment protocol as used in pediatric patients. One patient fully completed the protocol, and has since maintained a complete response (CR) for 2 years following completion of the treatment. The other patient also achieved CR after induction therapy, and is now undergoing maintenance therapy in an outpatient clinic. The cases presented in this study suggest that intensified systemic chemotherapy as used for pediatric patients with MS-LCH is well tolerated and effective for adult patients as well.