[Analysis of 7 cases of childhood blastic plasmacytoid dendritic cell neoplasm]

Objective: To evaluate the clinical characteristics, pathology, treatment, and prognosis of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in children. Methods: Clinical data (including gender, age of disease onset, affected sites, treatment, timing of allogeneic hematopoietic stem cell transplantation (allo-HSCT), etc.) of 7 children with BPDCN who were admitted to Beijing Children's Hospital, Capital Medical University from December 2018 to December 2023 were analyzed retrospectively. Clinical outcomes were also assessed, with patients followed up until December 2024. Results: Among 7 patients, there were 3 males and 4 females. Age at disease onset ranged from 3.2 to 12.9 years. Initial presentations included subcutaneous nodules in 5 cases, rash in 1 case, and ankle pain in 1 case. Extra-cutaneous involvement was seen in the bone marrow, lymph nodes, and central nervous system. six patients received induction chemotherapy using a modified Lymphoblastic lymphoma LBL regimen, 1 patient received the high-risk protocol for pediatric lymphoblastic lymphoma/leukemia and salvage therapy regimens. Allo-HSCT was performed soon after chemotherapy remission. The time to bridge allo-HSCT was 3.5 to 6.5 months. The follow-up time was 1.6 to 6.0 years. Six patients were in disease-free survival, while one patient survived with disease after recurrence following transplantation. Conclusions: BPDCN is rare in children and presents were with diverse clinical manifestations, with skin involvement being the predominant feature. Early allo-HSCT following complete remission with chemotherapy can improve prognosis.