Blastic plasmacytoid dendritic cell neoplasm frequently shows occult central nervous system involvement at diagnosis and benefits from intrathecal therapy

// Lourdes Martín-Martín 1 , Julia Almeida 1 , Helena Pomares 2 , Eva González-Barca 2 , Pilar Bravo 3 , Teresa Giménez 4 , Cecilia Heras 5 , José-Antonio Queizán 6 , Elena Pérez-Ceballos 7 , Violeta Martínez 8 , Natalia Alonso 9 , Carlota Calvo 10 , Rodolfo Álvarez 11 , María Dolores Caballero 12 and Alberto Orfao 1 1 Cancer Research Centre (IBMCC, USAL-CSIC), Institute for Biomedical Research of Salamanca (IBSAL) and Department of Medicine and Cytometry Service (NUCLEUS Research Support Platform), University of Salamanca (USAL), Salamanca, Spain 2 Hematology Department, Institut Catalá d’Oncologia, Hospital Duran i Reynals, University of Barcelona, Institut d’Investigació Biomèdica de Bellvitge, Barcelona, Spain 3 Hematology Department, University Hospital of Fuenlabrada, Madrid, Spain 4 Hematology Department, University Hospital Joan XXIII, Tarragona, Spain 5 Hematology Department, Infanta Leonor Hospital, Madrid, Spain 6 Hematology Department, Hospital of Segovia, Segovia, Spain 7 Hematology Department, University Hospital Morales Meseguer, Murcia, Spain 8 Hematology Department, Hospital of León, León, Spain 9 Hematology Department, University Hospital of Santiago, Santiago de Compostela, Spain 10 Hematology Department, University Hospital Miguel Servet, Zaragoza, Spain 11 Hematology Department, General Yagüe Hospital, Burgos, Spain 12 Hematology Department and IBSAL, University Hospital of Salamanca, Salamanca, Spain Correspondence to: Alberto Orfao, email: // Keywords : blastic plasmacytoid dendritic cell neoplasm, central nervous system, intrathecal prophylaxis, ALL therapy, flow cytometry Received : January 12, 2016 Accepted : January 21, 2016 Published : January 31, 2016 Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive myeloid neoplasm which shows a high rate of central nervous system (CNS) recurrence and overall survival (OS) of <1 year. Despite this, screening for CNS involvement is not routinely performed at diagnosis and intrathecal (IT) prophylaxis is not regularly administered in BPDCN. Here, we prospectively evaluated 13 consecutive BPDCN patients for the presence of CNS involvement by flow cytometry. Despite none of the patients presented with neurological symptoms, occult CNS involvement was detected in 6/10 cases evaluated at diagnosis and 3/3 studied at relapse/progression. BPDCN patients evaluated at diagnosis received IT treatment -either CNS prophylaxis ( n = 4) or active therapy ( n = 6)- and all but one remain alive (median follow-up of 20 months). In contrast, all three patients assessed at relapse/progression died. The potential benefit of IT treatment administered early at diagnosis on OS and CNS recurrence-free survival of BPDCN was further confirmed in a retrospective cohort of another 23 BPDCN patients. Our results show that BPDCN patients studied at diagnosis frequently display occult CNS involvement; moreover, they also indicate that treatment of occult CNS disease might lead to a dramatically improved outcome of BPDCN.