Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease): response to methotrexate and mercaptopurine.

We report a 3-year-old girl presenting with bilateral cervical lymph node enlargement persisting for > 3 months. Leukocytosis, elevated erythrocyte sedimentation rate, a marked hypergammaglobulinemia, and a moderate hepatosplenomegaly were also found. The diagnosis of sinushistiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease, was established histologically by the demonstration of characteristic sinushistiocytosis with lymphocytophagocytosis. Treatment was started with high dose steroids, and a decline of lymph node size and a normalization of laboratory parameters occurred. However, when steroids were tapered, lymph node size rapidly reincreased. Chemotherapeutic treatment was started using etoposide, which was completely ineffective. Therefore, treatment was changed to a combinatory low dose methotrexate therapy and 6-mercaptopurine for 4 months. Whereas a prompt and complete remission was reached, single 6-mercaptopurine therapy was maintained and treatment has been discontinued after a total of 2 years. The child has remained healthy for 7 years. This case would recommend the use of methotrexate and 6-mercaptopurine for treatment of complicated SHML.