Blastic plasmacytoid dendritic cell neoplasm (BPDCN): international, multi-center collaboration and global registry program

Background: Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) is a rare and aggressive hematologic malignancy originating from plasmacytoid dendritic cell precursors. BPDCN shares common diagnostic and clinical features with other hematologic malignancies and various dermatological disorders. Differential diagnosis and treatment are challenging and require awareness by the dermatologist, hemato-oncologist, pathologist for detailed diagnostic and therapeutic workup. The outcomes remain poor, and the optimal treatment for the disease is yet to be established, emphasizing the need for a more comprehensive and globally inclusive approach. Methods: In response to these challenges, we initiated an international, multi-center collaboration and established a global registry program for BPDCN patients. The registry collected both retrospective and prospective data on demographics, clinical presentations, diagnostic criteria, treatment regimens, and outcomes for cases diagnosed after Jan 2010. Data for this report was obtained from 36 patients across 16 centers in 12 countries, with ongoing contributions from additional centers. Results: Preliminary analysis revealed a male predominance (78%), with a median age at diagnosis of 63 years, involving all age groups. The immunophenotype (CD123 + , CD4 + , CD56 +) was consistently observed in a majority of patients (88.8%), validating its diagnostic utility and paramount significance in the BPDCN diagnosis. Treatment responses varied based on initial regimens, with ALL-like approaches demonstrating more favorable outcomes compared to AML-like strategies, which were given to younger patients. Notably, relapse rates remained high. Conclusion: The BPDCN International Registry Program provides a valuable tool in consolidating global data and fostering collaboration among researchers and clinicians. This collaborative effort involving multiple countries on several continents not only aims to advance our comprehension of BPDCN but also lays the groundwork for standardized treatment protocols for improving outcomes for BPDCN patients worldwide.