Blastic plasmacytoid dendritic cell neoplasm: skin and bone marrow infiltration of three cases and the review of the literature

A Case of Cutaneous Blastic Plasmacytoid Dendritic Cell Neoplasm on the Chest

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive blood cancer that often presents with skin lesions and can involve other organs, including the bone marrow. Despite initial responses to treatment, most patients eventually experience disease progression. We report the case of an 82-year-old male with a red chest nodule, later diagnosed with BPDCN and acute myeloid leukemia (AML). Dermoscopy revealed reddish-purple dots, and a biopsy confirmed BPDCN. The patient responded to venetoclax and azacitidine but relapsed five months later. This case highlights the importance of early diagnosis of BPDCN and the utility of dermoscopy in this tumor, which can contribute to timely treatment and improved patient outcomes.

Updates in Novel Therapies for Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN)

PURPOSE OF REVIEW

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, clinically aggressive hematologic malignancy that has heterogeneous presentation and can involve the skin, lymph nodes, and bone marrow. Recent advancements in our patho-biologic understanding of the disease have led to the development of new targeted therapies for BPDCN. In this review, we aimed to describe some of the novel treatments that are being put forward for the management of BPDCN.

RECENT FINDINGS

Tagraxofusp is the first CD123-targeted therapy approved as the first ever targeted treatment of BPDCN in patients aged 2 years and older. This agent was approved based on a pivotal clinical trial that showed that it was associated with high rates of clinical responses in both treatment-naïve and treatment-experienced patients. The most serious adverse event was occurrence of the capillary leak syndrome. Other targeted therapies are actively being investigated in clinical trials. These include other CD123-targeted approaches, as well as active investigation in targets beyond CD123, such as the BCL-2 inhibitor, venetoclax. BPDCN is a rare hematologic clonal disorder with historically poor outcomes. Newer targeted therapies have been recently introduced, with promising results and novel toxicities that are important to recognize and understand. Stem cell transplantation after achievement of complete remission remains the mainstay of therapy among younger/fit, eligible patients, regardless of treatment modality used.

Blastic Plasmacytoid Dendritic Cell Neoplasm: Single Center Experience on a Rare Hematological Malignancy

Purpose

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and poor prognostic hematological malignancy. There is still no standard treatment established for BPDCN patients. We aim to summarize the main clinical, biological features and treatment of 9 BPDCN patients.

Methods

Nine patients with BPDCN who had been diagnosed between July 2008 and December 2018 in Ankara University School of Medicine, were retrospectively evaluated.

Results

All patients (n = 9) were male, median age was 64 (21-80). Five patients (55.6%) had bone marrow infiltration, 5 patients (55.6%) cutaneous lesions, 6 patients (66.7%) lymph node involvement, 2 patients (22.2%) central nervous system involvement and 2 patients (22.2%) spleen involvement at time of diagnosis. Complex karyotype was observed in 2 patients. CHOP was given to 5 patients (55.6%), hyper-CVAD to 2 patients (22.2%), fludarabine, cyclophosphamide and mitoxantrone to 1 patient (11.1%) and cyclophosphamide, etoposide, methylprednisolone to 1 patient (11.1%) as first line chemotherapy. Four patients (44.4%) underwent allogeneic hematopoietic stem cell transplantation (AHSCT) in complete remission (CR) 1. Venetoclax was given to a transplant ineligible patient who had skin and lymph node involvement, with the off-label use. The median follow-up time was 15.9 months (3-48.6 months). Estimated median overall survival was 15.9 + 1.6 (95% CI 12.7-19.1) months.

Conclusion

Intensive induction therapies followed by AHSCT in CR seems to be best approaches for patients with BPDCN. Thus, more effective treatment strategies particularly targeted therapies should be warranted to improve the survival of patients with this rare disease.

Dendritic Cell Leukemia: a Review

PURPOSE OF REVIEW

The purpose of this review was to summarize the clinical, diagnostic, and therapeutic features of blastic plasmacytoid dendritic cell neoplasm (BPDCN).

RECENT FINDINGS

Several case reports and series revealed new clinical, molecular, diagnostic, and therapeutic aspects of the disease. The clinical presentation diversity has been confirmed, with frequent leukemic non-cutaneous or rare atypical manifestations. The clonal evolution in the development of BPDCN has not been sufficiently elucidated. Although certain immunophenotypic markers (CD4, TCL1, CD123, CD56, CD303) are indicative of BPDCN, the diagnosis remains in certain cases challenging. Adult (ALL)-type chemotherapy followed by hematopoietic stem cell transplantation (HSCT) is related to a favorable outcome, while chemotherapy alone seems enough in children. Future studies should continue to investigate whether CD123-directed therapies could be utilized. BPDCN is a rare aggressive malignancy that needs an aggressive induction therapy. Although a diagnostic consensus is still lacking, and large retrospective studies are also needed to obtain standardized treatment guidelines, the future perspectives are encouraging, because of novel therapeutic agents that are under investigation.

Chemotherapy Options for Blastic Plasmacytoid Dendritic Cell Neoplasm

BPDCN is ultimately a bone marrow disease requiring induction-type eradication therapy followed by hematopoietic stem cell transplant (HSCT) to achieve long-lasting remissions or cure. Various regimens have been applied to this disease with varying success. A cumulative review of the literature suggests more intense regimens have greater efficacy with acute lymphoblastic leukemia regimens preferred to acute myeloid leukemia regimens. This approach benefits fit patients who are eligible for HSCT; however, most BPDCN patients require other treatment options. The recent FDA approval of the CD123-targeted agent tagraxofusp provides a novel therapeutic alternative to traditional chemotherapy but with potential toxicities.

New perspectives in genetics and targeted therapy for blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is one rare but clinically aggressive hematological malignancy, and it is typically characterized by skin lesion and bone marrow involvement. Diagnosis of BPDCN relies on the immunophenotype positive for four of CD4, CD56, CD123, TCL1 and BDCA-2, and commonly without the expression of MPO, cytoplasmic CD3, CD13, CD64, cytoplasmic CD79a, CD19 and CD20. Commonly, BPDCN is characterized by high CD123 expression, aberrant NF-κB activation, dependence on TCF4-/BRD4-network, and deregulated cholesterol metabolism. Under conventional therapy, the survival duration is only improved in a small number of BPDCN patients. Therefore, targeted therapy should be developed. Up to now, tagraxofusp is the leading edge and has been approved for BPDCN treatment. However, most of other targeted therapy agents were still not pushed to clinical trials for BPDCN. In this review, we emphatically discuss recent perspectives on BPDCN genetic features and developments of its targeted therapy.

Recent developments in the treatment of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive hematologic malignancy derived from precursors of dendritic cells and involves most frequently the skin, bone marrow and lymph nodes. Diagnosis depends upon identification of specific tumor markers including CD4, CD56 and CD123. Historically, the median survival has been less than 2 years in most reported series. While for many years, conventional chemotherapy followed by stem cell transplantation was the standard of care, recently tagraxofusp, a cytotoxin directed against CD123, received United States Food and Drug Administration approval specifically for patients with BPDCN. In this review, we will discuss the markers used for diagnosis of BPDCN and focus on the new targeted treatments available. Specifically in BPDCN, tagraxofusp was highly effective with a safety profile found to be acceptable overall, with the noted occurrence of capillary leak syndrome. Future directions in therapy approaches for patients with BPDCN will include the development of other CD123-targeted agents, agents targeting beyond CD123 and investigation of rational combination approaches of CD123-directed therapy with other therapies.

Pediatric Blastic Plasmacytoid Dendritic Cell Neoplasm: A Systematic Literature Review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive hematologic malignancy characterized by frequent skin involvement that most commonly affects older patients. BPDCN is known to have a poor prognosis. Our objective was to assess if outcome and disease prognosis were independently influenced by age when evaluated with clinical presentation, sex, and treatment regimens. We conducted a systematic review to identify BPDCN cases, to compare pediatric BPDCN cases with adult cases. A total of 125 publications were identified detailing 356 cases. Including 1 pediatric case from our institution, 74 were children, and 283 were adults aged 19 or over. Age was shown to be an independent prognostic factor predictive of more favorable outcomes across measures including initial response to therapy, likelihood of relapse, and overall survival at follow-up. The distribution of affected organs at diagnosis was similar across children and adults and type of clinical presentation did not disproportionately influence 1 age group's prognosis over the other. Acute lymphoblastic leukemia-type chemotherapy regimens were shown to be superior to other chemotherapy regimens (acute myeloid leukemia, lymphoma, acute lymphoblastic leukemia/lymphoma, other, or none) in inducing complete remission. Allogeneic stem cell transplantation was shown to increase mean survival time. Future research may be directed toward elucidating the further morphologic, cytogenetic, and cytochemical differences between younger and older BPDCN patients.