Hemophagocytic lymphohistiocytosis in systemic mastocytosis treated with allogeneic bone marrow transplant: A case report.

Systemic mastocytosis is a rare entity in pediatrics, usually associated with mutations in the c-KIT gene. We describe a Caucasian female who presented with severe systemic mastocytosis with food allergies requiring prolonged total parenteral nutrition. Her course was further complicated by the onset of hemophagocytic lymphohistiocytosis, which responded poorly to conventional chemotherapy. She underwent an allogeneic hematopoietic stem cell transplant that resulted in resolution of all symptoms related to systemic mastocytosis and hemophagocytic lymphohistiocytosis. She is now disease-free and without any complications two years after the transplant.