Allogeneic Hematopoietic Stem Cell Transplantation for Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm is a rare malignancy that typically follows a highly aggressive clinical course,formerly known as blastic natural killer (NK)-cell lymphoma and CD4+/CD56+ hematodermic neoplasm. Here we report 2 cases of blastic plasmacytoid dendritic cell neoplasm that underwent allogeneic stem cell transplantation.

Case one was recognized as acute lymphocyte leukemia and then was revised to BPDC at recurrence, and another initially presented with typical cutaneous involvement and was promptly diagnosed by biopsy. After induction/re-induction and subsequent consolidation chemotherapy, 2 cases of BPDC received HLA identical-sibling donor allogeneic stem cell transplantation (Allo-HSCT) after BU/Cy, TBI/Cy+VP-16 conditioning regimen, respectively. Both achieved rapid hematopietic recovery in 2 weeks. Multi-color labeling flow cytometry was performed to monitor minimal residual disease (MRD) and the patient received donor lymphocyte infusion (DLI) to control primary malignancy as MRD-triggered or preventive strategy.

Case 1 survived refractory acyclovir-resistant Epstein-Barr virus viremia after rituximab treatment, but failed in DLI-related grade IV graft versus host disease (GVHD) mixed with thrombotic microangiopathy (TMA) on 1 year post-transplantation. Case 2 died from relapse.

Allo-HSCT seems to be a promising treatment for aggressive BPDC aided with MRD monitoring and MRD-triggered DLI. GVHD mixed with TMA deserves more attention for treatment of refractory GVHD.

No relevant conflicts of interest to declare.