Diffuse lung metastases in a child with blastic plasmacytoid dendritic cell neoplasm and review.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, highly aggressive hematopoietic malignancy, characterized by cutaneous and bone marrow involvement and leukemic spread. Cutaneous involvement is the most common presentation in BPDCN. At present, the diagnosis and management of BPDCN are still challenging. Due to its rarity, the pediatric experience with BPDCN is especially limited. Herein, we report a special case of BPDCN with diffuse nodular lung metastases and a cutaneous lesion, which achieved a dramatic response to non-Hodgkin lymphoma regimen and remained with complete remission for 2 years. To date, acute lymphoblastic leukemia (ALL)-type chemotherapy followed by hematopoietic stem cell transplantation (SCT) is commonly thought to be related to a favorable outcome in adults with BPDCN. In contrast to it, ALL or non-Hodgkin lymphoma-type therapy alone seems enough in children with BPDCN with or without cutaneous lesions. SCT should only be performed for children who relapse and achieve a second remission. For pediatric BPDCN, further study of larger numbers of cases is needed to better define prognostic factors and optimal treatment strategy, and understand the underling differences in pathogenesis between children and adults.