Systemic mastocytosis associated with Hodgkin's lymphoma in a 4-year-old child.

Systemic mastocytosis with associated clonal hematologic non-mast cell lineage disease (SM-AHN) represents a specific subtype of mastocytosis and is extremely rare in children. We describe a 4-year-old child with systemic mastocytosis associated with Hodgkin's lymphoma. The child had cutaneous mastocytosis and lymphadenopathy without other clinical features of SM, which was diagnosed only by bone marrow examination.