PB2398: BLASTIC PLASMACYTOID DENDRITIC CELL NEOPLASIA IN 2 CENTERS OF BOGOTÁ – COLOMBIA: THE LARGEST CASE SERIES IN LATIN AMERICA

Topic: 20. Lymphoma Biology & Translational Research Background: Blastic Plasmacytoid Dendritic Cell neoplasia or BPDCN has an aggressive clinical behavior with a very poor prognosis and high mortality. It represents a proportion of only 0.44% of hematological malignancies. Diagnosis is based on the immunophenotype on bone marrow and skin lesions´ samples. Treatment varies between intensive treatments, monoclonal antibodies, and hematopoietic progenitor transplantation. We present the largest cohort of patients with BPDCN described to date in Latin American patients. Aims: To describe and analyze the demographic, clinical, and paraclinical characteristics of 8 patients treated in 2 reference centers in the country. Methods: Data of patients diagnosed with BPCDN between 2007 and 2023 was collected. Diagnosis was made with biopsy of skin lesions and bone marrow. After an adequate classification and diagnosis of the disease, 8 of 9 patients were included in the case series. Results: A total of 8 patients were diagnosed. Most of the patients were male (5:3), with a mean age of 62 years (20-85 years). All patients had dermatological lesions at diagnosis (figure 1). Half of the cases presented splenomegaly. Seven patients (87.5%) had bone marrow involvement. Of these, 100% had a positive immunophenotype for HLA DR+, CD4+, CD123+, and CD56, with heterogeneous positivity for CD117, and CD45. Regarding treatment, four patients (50%) received HyperCVAD, one patient cytarabine + idarubicin, one patient CHOP, and one patient 5-azacitidine + venetoclax. Four died from complications associated with disease progression or treatment complications. Three patients are still alive, of which one is still undergoing treatment. Overall survival was 9.8 months (range 3 weeks to 16 months). Only one patient (12.5%) underwent allogeneic stem cell transplantation (Table 1). Summary/Conclusion: Blastic plasmacytoid dendritic cell neoplasm is a rare entity, with small case series reported in the literature. It is a disease with a clinical aggressive behavior, which mostly affects the skin and bone marrow. Treatment is usually based on high-intensity chemotherapy. We recognize the need to create collaborative groups dedicated to strengthening knowledge around this disease to improve outcomes for patients around the world. - Patient Age Gender BM Involvement Skin Involvement BM immunophenotype Skin immunophenotype Treatment OS (months) 1 20 F Yes Yes HLA DR+, CD123+, CD56+, CD4 -/+, CD117- No data Cytarabine + Idarubicin (7 + 3) 14 2 85 M Yes Yes HLA DR+, CD123+, CD56+, CD4 -/+, CD117+, CD45+ No data CHOP 1 3 61 M Yes Yes HLA DR+, CD123+, CD56+, CD4 -/+, CD117+, CD45 -/+ No data HyperCVAD 6 4 81 M Yes Yes HLA DR+, CD123+, CD33 -/+, CD4+, CD45 -/+ CD4+, CD56+ Not received No data 5 50 F Yes Yes HLA DR+, CD123+, CD56+, CD4+, CD45 -/+ CD4+, CD56+ HyperCVAD + Allo SCT Not reached 6 56 M Yes Yes HLA DR+, CD123+, CD56+, CD4+, CD7+, CD45+ No data HyperCVAD 16 7 67 F Yes Yes HLA DR+, CD123+, CD56+, CD4+, CD45 -/+ CD4+, CD56+ HyperCVAD Not reached 8 82 M No Yes No involvement CD4+, CD56+, CD123 -/+, CD33 -/+ 5-Azacitidine + Venetoclax Not reached Table 1. Clinical characteristics, including treatment details of 8 patients with blastic plasmacytoid dendritic cell neoplasm treated in 2 reference centers in Bogotá D.C., Colombia. BM: Bone marrow, OS: overall survival; CHOP: cyclophosphamide, hydroxidaunorubicine, vincristine, prednisone; HyperCVAD: cyclophosphamide, vincristine, doxorubicine, dexamethasone, methotrexate, cytarabine.Figure 1. Dermatologic lesions of patients 6, 7 and 8 at diagnosis, respectively. Keywords: Plasma cells, Dendritic cell, Lymphoma, NK cell