Blastic plasmacytoid dendritic cell neoplasm: a clinicopathologic review

Optimization of Adcitmer, a Monomethyl-Auristatin E bearing antibody-drug conjugate for the treatment of CD56-expressing cancers

The cell adhesion protein CD56 has been identified as a potential therapeutic target in several solid tumors and hematological malignancies. Recently, we developed a CD56-directed antibody-drug conjugate (ADC), called Adcitmer and demonstrated its antitumor properties in preclinical models of the rare and aggressive skin cancer Merkel cell carcinoma (MCC).The present study aims to further optimize Adcitmer to overcome the therapeutic limitations observed with previously evaluated CD56-targeting ADCs, which were partially related to toxic effects on leukocytes. To this end, we aimed to avoid interaction of Adcitmer with immune cells via Fc gamma receptor (FcγR) binding. Since glycosylation is essential for FcγR binding, an aglycosylated form of Adcitmer was generated and evaluated on human leukocytes and MCC cell lines using cell death (annexin V/7-aminoactinomycine D) and proliferation (2,3-Bis-(2-methoxy-4Nitro-5-sulfophenyl)-2H-tetrazolium-5carboxanilide) assays. Finally, the therapeutic performance of Adcitmer and its aglycosylated form was assessed in an MCC xenograft mouse model.Investigating the Adcitmer interaction with immune cells demonstrated that it is mostly mediated by Fc recognition. Accordingly, Adcitmer aglycosylation led to reduced immune cell toxicity and strikingly also to improved therapeutic performance even in an MCC xenograft model using immunodeficient mice.Our study suggests that aglycosylated Adcitmer should be considered as a therapeutic option in patients with advanced MCC or other CD56-positive tumors.

A Multidisciplinary Approach to Diagnosing Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN): Practical Recommendations and Insights from Countries of the Gulf Cooperation Council

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive orphan hematopoietic malignancy characterized by cutaneous and systemic hematologic involvement. BPDCN is frequently misidentified, but early, accurate diagnosis is critical to extending patient survival using tagraxofusp, a first-in-class CD123-targeted therapy, and increasing their chances of receiving a potentially curative stem cell transplantation. Cases of BPDCN in countries of the Gulf Cooperation Council are lower than the extrapolated incidence from other geographic locations due to lack of awareness of key diagnostic features, lack of consensus on the minimal phenotype for diagnosis, and lack of local immunohistochemistry testing facilities, contributing to underdiagnosis in this region. Practical recommendations, a streamlined diagnostic panel, and suggested multidisciplinary approaches based on expert experience regarding diagnostic and clinical challenges specific to this region, and a review of the literature are presented here to facilitate diagnosis of BPDCN in this region by primary care physicians, dermatologists, and hematologists.

Breakthrough in Blastic Plasmacytoid Dendritic Cell Neoplasm Cancer Therapy Owing to Precision Targeting of CD123

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic cancer originating from the malignant transformation of plasmacytoid dendritic cell precursors. This malignancy progresses rapidly, with frequent relapses and a poor overall survival rate, underscoring the urgent need for effective treatments. However, diagnosing and treating BPDCN have historically been challenging due to its rarity and the lack of standardized approaches. The recognition of BPDCN as a distinct disease entity is recent, and standardized treatment protocols are yet to be established. Traditionally, conventional chemotherapy and stem cell transplantation have been the primary methods for treating BPDCN patients. Advances in immunophenotyping and molecular profiling have identified potential therapeutic targets, leading to a shift toward CD123-targeted immunotherapies in both clinical and research settings. Ongoing developments with SL-401, IMGN632, CD123 chimeric antigen receptor (CAR) T-cells, and bispecific antibodies (BsAb) show promising advancements. However, the therapeutic effectiveness of CD123-targeting treatments needs improvement through innovative approaches and combinations of treatments with other anti-leukemic drugs. The exploration of combinations such as CD123-targeted immunotherapies with azacitidine and venetoclax is suggested to enhance antineoplastic responses and improve survival rates in BPDCN patients. In conclusion, this multifaceted approach offers hope for more effective and tailored therapeutic interventions against this challenging hematologic malignancy.

A Case of Acute Myeloid Leukemia Mimicking Blastic Plasmacytoid Dendritic Cell Neoplasm: Utility of the Proposed Upcoming WHO-5 Diagnostic Criteria

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive hematologic malignancy which is associated with a distinctive morphologic appearance. However, the morphology is not specific, and diagnostic characterization requires integration of immunophenotypic and genetic testing. We herein report a case of a 35-year-old female patient who presented with worsening cytopenia. A bone marrow aspirate identified medium-sized blastic cells with perinuclear microvacuoles ("pearl neckless"). Occasional blasts demonstrated a "hand mirror" appearance. Tandem flow cytometry showed an atypical population of dim CD45 events with expression of CD4, CD56, CD117, CD123, and monocytic markers such as CD64. Fluorescence in situ hybridization (FISH) showed evidence of a KMT2A rearrangement with an unknown partner on chromosome 19. Expression of MPO and muramidase was present. The final diagnosis was acute monocytic leukemia (AMoL). Due to the overlapping features of acute myeloid leukemia and BPDCN, the 5th Edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours provides new criteria for the diagnosis of BPDCN. Our case highlights the utility of these criteria.

Patients with blastic plasmacytoid dendritic cell neoplasm in pregnancy: A rare case report

RATIONALE

Previous clinical reports of patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) in pregnancy are rare.

PATIENT CONCERNS

The present study presents the case of 37-year-old women exhibiting third trimester with progressive painless, abdominal skin nodules.

INTERVENTIONS AND OUTCOMES

A 37-year-old pregnant woman with BPDCN and partial placenta previa and racket-shaped placenta. After comprehensive evaluation, the pregnancy status ends at 37 weeks and 6 days by cesarean section of lower uterus and no abnormality in the newborn.

LESSONS

Pregnant women diagnosed with BPDCN in the third trimester should terminate the pregnancy promptly for further treatment.

Global assessment of IRF8 as a novel cancer biomarker

Interferon regulatory factor 8 (IRF8) is a member of the IRF family that is specific to the hematopoietic cell and is involved in regulating the development of human monocytic and dendritic-lineage cells, as well as B-cells. Because its utility as a sensitive and specific monoblast marker in the context of acute monocytic leukemias has been recently demonstrated, we hypothesized that it may also be useful as a novel immunohistochemical marker in myeloid sarcomas and blastic plasmacytoid dendritic cell neoplasms (BPDCNs) with respect to their differential diagnoses. In this retrospective study, we analyzed the IHC expression pattern of IRF8 in 385 patient samples across 30 types of cancers, referenced to their mRNA expression data available through The Cancer Genome Atlas. In addition, we assessed IRF8 in 35 myeloid sarcomas and 15 BPDCNs. Twenty-four of 35 cases of myeloid sarcomas (68.5%) showed positivity for IRF8, with six cases (17.1%) demonstrating IRF8 expression in the absence of CD34 and MPO. All 15 of 15 BPDCNs (100%) showed strong uniform expression of IRF8 and were occasionally more definitive than CD123. IRF8 was negative in all desmoplastic small round cell tumors, Ewing sarcomas, synovial sarcomas, and undifferentiated pleomorphic sarcomas, as well as all epithelial malignancies tested except for 2 triple negative breast cancers that showed subset weak staining. In conclusion, IRF8 is a novel marker helpful in identifying extranodal hematopoietic tumors that can otherwise be difficult to diagnose given the broad differential diagnoses and frequent loss of more common lineage-defining markers.

Blastic Plasmacytoid Dendritic Cell Neoplasm: A Rare Case Report with Literature Review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematopoietic neoplasm for which there are no effective therapies. We present a 70-year-old male patient with multiple reddish painless, nonpruritic, and nonpedunculated nodules over the trunk, forearm, and thighs for a duration of 3 months. The nodules measured 0.5 to 2 cm in diameter. The peripheral smear findings were within normal limits. Excision biopsy was performed. Histomorphology and immunohistochemistry (CD123, CD 56, CD4, HLA-DR, CD43, and CD68) confirmed the diagnosis of BPDCN. Findings of marrow aspiration, biopsy and imaging studies were within normal limits. Patient demonstrated a good response with complete disappearance of all nodules by initial 2 weeks of therapy with a modified Berlin–Frankfurt–Munster (BFM) acute lymphoblastic leukemia (ALL) protocol and has completed 8 doses (LSAP [lincosamides, streptogramins A and pleuromutilins chemotherapy], 5,000 units/m2). The patient tolerated protocol extremely well.

Blastic Plasmacytoid Dendritic Cell Neoplasm: Progress in Cell Origin, Molecular Biology, Diagnostic Criteria and Therapeutic Approaches

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy characterized by recurrent skin nodules, an aggressive clinical course with rapid involvement of hematological organs, and a poor prognosis with poor overall survival. BPDCN is derived from plasmacytoid dendritic cells (pDCs) and its pathogenesis is unclear. The tumor cells show aberrant expression of CD4, CD56, interleukin-3 receptor alpha chain (CD123), blood dendritic cell antigen 2 (BDCA 2/CD303), blood dendritic cell antigen 4 (BDCA4) and transcription factor (E protein) E2-2 (TCF4). The best treatment drugs are based on experience by adopting those used for either leukemia or lymphoma. Relapse with drug resistance generally occurs quickly. Stem cell transplantation after the first complete remission is recommended and tagraxofusp is the first targeted therapy. In this review, we summarize the differentiation of BPDCN from its cell origin, its connection with normal pDCs, clinical characteristics, genetic mutations and advances in treatment of BPDCN. This review provides insights into the mechanisms of and new therapeutic approaches for BPDCN.

E-Cadherin Expression in Blastic Plasmacytoid Dendritic Cell Neoplasms: An Unrecognized Finding and Potential Diagnostic Pitfall

E-cadherin is expressed in hematopoietic erythroid precursors, but to our knowledge, its expression in blastic plasmacytoid dendritic cell neoplasm (BPDCN) has not been described. We report a case of BPDCN showing strong expression of E-cadherin, arising in a patient with history of primary myelofibrosis. Four more cases of BPDCN tested all showed strong expression of E-cadherin. Lack of awareness of this pattern of expression may lead to erroneous diagnosis of acute erythroid leukemia. It is increasingly becoming important to correctly identify this group of neoplasms, as approved new anti-CD123-targeted therapies are becoming available.

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.

Features of non-activation dendritic state and immune deficiency in blastic plasmacytoid dendritic cell neoplasm (BPDCN)

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, male-predominant hematologic malignancy with poor outcomes and with just one recently approved agent (tagraxofusp). It is characterized by the abnormal proliferation of precursor plasmacytoid dendritic cells (pDCs) with morphologic and molecular similarities to acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)/chronic myelomonocytic leukemia (CMML) in its presentation within the bone marrow and peripheral blood. To identify disease-specific molecular features of BPDCN, we profiled the bone marrow, peripheral blood, and serum samples from primary patient samples using an in-house hematologic malignancy panel ("T300" panel), transcriptome microarray, and serum multiplex immunoassays. TET2 mutations (5/8, 63%) were the most prevalent in our cohort. Using the transcriptome microarray, genes specific to pDCs (LAMP5, CCDC50) were more highly expressed in BPDCN than in AML specimens. Finally, the serum cytokine profile analysis showed significantly elevated levels of eosinophil chemoattractants eotaxin and RANTES in BPDCN as compared with AML. Along with the high levels of PTPRS and dendritic nature of the tumor cells, these findings suggest a possible pre-inflammatory context of this disease, in which BPDCN features nonactivated pDCs.

Blastic Plasmacytoid Dendritic Cell Neoplasia: A Single Center Experience

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignancy with skin tropism. The entity was recently defined and the diagnosis is generally made by skin biopsies. It is necessary to apply appropriate immunohistochemistry to recognize this rare entity. There is no consensus on therapy and the survival rates are low. The aim of this study is to describe the clinical and histopathological features of BPDCN. We retrospectively reviewed 8 BPDCN cases of the Cerrahpaşa Medical Faculty diagnosed between 2005 and 2019. We documented the clinical findings, histopathologic diagnoses, and outcomes. The mean age of the patients was 58.7 years (range=11-86 years), and 7 patients were male. The patients presented with erythematous or purple papules, plaques, and papulonodular or nodular cutaneous lesions. Two had lymphadenomegaly at presentation. In microscopic evaluations, tumor cells infiltrated the entire dermis with a clear-cut subepidermal Grenz zone in all cases. CD4, CD56, and CD123 were the most frequently expressed immunohistochemical markers. The median follow-up of 7 cases was 14 months, ranging from 6 to 48 months. Three patients died of the disease, while 4 patients were still alive. Out of 7 patients, 5 received chemotherapy. We found that the outcomes of some patients were different from others but we did not link any distinct clinical or histopathological characteristics to these different outcomes.

An Unusual Manifestation of Blastic Plasmacytoid Dendritic Cell Neoplasm as a Testicular Tumor

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive hematologic malignancy arising from precursors of plasmacytoid dendritic cells that represent less than 1% of hematological malignancies. BPDCN initially presents with cutaneous involvement and a characteristic immunophenotype of CD4, CD56, and CD123 co-expression. Upon disease progression, BPDCN shows a strong predilection for bone marrow, peripheral blood, and lymph nodes, whereas manifestations in visceral organs are rare. Significant heterogeneity in clinical presentation and immunophenotypic profile makes BPDCN challenging to diagnose without an integrated approach based on patient history, clinical features, tumor pathology, and comprehensive immunohistochemical studies. Herein we report the first case of relapsed BPDCN manifesting as a unilateral testicular tumor.

Blastic plasmacytoid dendritic cell neoplasm in the background of myeloproliferative disorder and chronic lymphocytic leukaemia

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare haematological malignancy defined by concurrent expression of CD4, CD56, BCL-2 and CD123. The disease has a very poor prognosis and there are no well-established treatment guidelines. We describe a case of BPDCN in a 65-year-old female patient with myeloproliferative disorder (essential thrombocythemia) and chronic lymphocytic leukaemia. She presented with rapidly progressive facial and scalp lesions. Skin biopsy confirmed BPDCN and the imaging revealed widespread disease. Patient was started on hyper-CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone) and intrathecal methotrexate. Due to progression on initial treatment, she was treated with decitabine and venetoclax (BCL-2 inhibitor). However, patient continued to deteriorate and died after 4 months from initial diagnosis. We emphasise on the clinical features, emerging treatment modalities and prognosis of BPDCN.

Single-Cell Transcriptomics in Cancer Immunobiology: The Future of Precision Oncology

Cancer is a heterogeneous and complex disease. Tumors are formed by cancer cells and a myriad of non-cancerous cell types that together with the extracellular matrix form the tumor microenvironment. These cancer-associated cells and components contribute to shape the progression of cancer and are deeply involved in patient outcome. The immune system is an essential part of the tumor microenvironment, and induction of cancer immunotolerance is a necessary step involved in tumor formation and growth. Immune mechanisms are intimately associated with cancer progression, invasion, and metastasis; as well as to tumor dormancy and modulation of sensitivity to drug therapy. Transcriptome analyses have been extensively used to understand the heterogeneity of tumors, classifying tumors into molecular subtypes and establishing signatures that predict response to therapy and patient outcomes. However, the classification of the tumor cell diversity and specially the identification of rare populations has been limited in these transcriptomic analyses of bulk tumor cell populations. Massively-parallel single-cell RNAseq analysis has emerged as a powerful method to unravel heterogeneity and to study rare cell populations in cancer, through unsupervised sampling and modeling of transcriptional states in single cells. In this context, the study of the role of the immune system in cancer would benefit from single cell approaches, as it will enable the characterization and/or discovery of the cell types and pathways involved in cancer immunotolerance otherwise missed in bulk transcriptomic information. Thus, the analysis of gene expression patterns at single cell resolution holds the potential to provide key information to develop precise and personalized cancer treatment including immunotherapy. This review is focused on the latest single-cell RNAseq methodologies able to agnostically study thousands of tumor cells as well as targeted single-cell RNAseq to study rare populations within tumors. In particular, we will discuss methods to study the immune system in cancer. We will also discuss the current challenges to the study of cancer at the single cell level and the potential solutions to the current approaches.

Clinicopathologic retrospective analysis of blastic plasmacytoid dendritic cell neoplasms

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is one of the aggressive rare hematopoietic malignancies with predilection to the skin, primarily found in adults. The precise incidence of BPDCN is difficult to estimate due to constantly changing nomenclature and lack of precise defining criteria prior to the 2008 WHO classification system. There are not many cases described in the literature, what makes the diagnostic process challenging. Skin lesions such as erythematous infiltrates and nodules are usually the first manifestation of the disease. Therefore, in doubtful diagnostic cases, dermatologists should perform histopathological and immunohistochemistry examinations along with hematological and oncological cooperation, as early diagnosis and appropriate treatment is essential for improvement of the disease course. This analysis, despite the small number of patients may provide useful information on the clinical and histopathological features of this rare malignancy.

A Challenging Blastic Plasmacytoid Dendritic Cell Neoplasm Case: Tough Decisions to Make

Blastic plasmacytoid dendritic cell neoplasm is a very rare disease and in our case report we discuss the presentation of our patient, her treatment and response in addition for a discussion of the newly therapeutic options that are available.

Blastic plasmacytoid dendritic cell neoplasm: challenges and future prospects

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare CD4+ CD56+ myeloid malignancy that is challenging to diagnose and treat. BPDCN typically presents with nonspecific cutaneous lesions with or without extra-cutaneous manifestations before progressing to leukemia. Currently, there is no standard of care for the treatment of BPDCN and various approaches have been used including acute myeloid leukemia, acute lymphoblastic leukemia, and lymphoma-based regimens with or without stem cell transplantation. Despite these treatment approaches, the prognosis of BPDCN remains poor and there is a lack of prospective data upon which to base treatment decisions. Recent work examining the mutational landscape and gene expression profiles of BPDCN has identified a number of potential therapeutic targets. One such target is CD123, the α subunit of the human interleukin-3 receptor, which is the subject of intervention studies using the novel agent SL-401. Other investigational therapies include UCART123, T-cell immunotherapy, and venetoclax. Prospective trials are needed to determine the best treatment for this uncommon and aggressive neoplasm.

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.

Blastic plasmacytoid dendritic cell neoplasm in children: A review of two cases

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a newly characterized, rare malignant tumor of the skin and hematopoietic system. BPDCN occurs mainly in the elderly, whereas it is rarer among children, and has variable clinical manifestations. Optimal chemotherapeutic regimens for the treatment of BPDCN have not yet been determined and this tumor has a poor prognosis. In this study, two pediatric cases of BPDCN, including a 7-year-old female and a 9-year-old male patient, diagnosed at the Xiangya Hospital of Central South University over the past 2 years, were retrospectively reviewed. Both cases exhibited multiple organ involvement, although the clinical manifestations differed; they were diagnosed with BPDCN based on the clinical manifestations, pathological and immunohistochemical findings, which included positivity for CD4, CD56 and CD123. A high-risk acute lymphocytic leukemia (ALL) chemotherapy regimen was administered to both patients. The patient in the first case achieved a complete remission, but unfortunately her parents refused follow-up treatment and she succumbed to the disease 9 months after the initial diagnosis. The second patient was treated for a total of three courses with a chemotherapy regimen including daunorubicin, cytarabine and etoposide, followed by two courses of the high-risk ALL chemotherapy regimen; unfortunately, a remission was not achieved and the patient was scheduled to receive hematopoietic stem cell transplantation. Thus, not all pediatric BPDCN patients may be able to achieve complete remission following chemotherapy with the high-risk ALL regimen, and other treatment options must be investigated in the future.

Treatment of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare myeloid malignancy with no defined standard of care. BPDCN presents most commonly with skin lesions with or without extramedullary organ involvement before leukemic dissemination. As a result of its clinical ambiguity, differentiating BPDCN from benign skin lesions or those of acute myeloid leukemia with leukemia cutis is challenging. BPDCN is most easily defined by the phenotype CD4⁺CD56⁺CD123⁺lineage^-MPO^-, although many patients will present with variable expression of CD4, CD56, or alternate plasmacytoid markers, which compounds the difficulty in differentiating BPDCN from other myeloid or lymphoid malignancies. Chromosomal aberrations are frequent, and the mutational landscape of BPDCN is being rapidly characterized although no obvious molecular target for chemoimmunotherapy has been identified. Chemotherapy regimens developed for acute myeloid leukemia, acute lymphoid leukemia, and myelodysplastic syndrome have all been used to treat BPDCN. Relapse is frequent, and overall survival is quite poor. Allogeneic transplantation offers a chance at prolonged remission and possible cure for those who are eligible; unfortunately, relapse remains high ranging from 30% to 40%. Novel therapies such as SL-401, a diphtheria toxin conjugated to interleukin-3 (IL-3) is commonly overexpressed in BPDCN and other aggressive myeloid malignancies and has shown considerable promise in ongoing clinical trials. Future work with SL-401 will define its place in treating relapsed or refractory disease as well as its role as a first-line therapy or bridge to transplantation.

An Unexpected Chink in the Transcriptional Armor of Plasmacytoid Dendritic Neoplasms

In this issue of Cancer Cell, Ceribelli et al. use functional genomic and chemical screening to reveal the existence of a TCF4/BRD4-dependent oncogenic regulatory network in blastic plasmacytoid dendritic cell neoplasm (BPDCN) and demonstrate that BPDCN cells are highly sensitive to therapeutic targeting of this novel dependency.

CT findings associated with blastic plasmacytoid dendritic cell neoplasm: a case report

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that is frequently misdiagnosed. We present a case of a 53-year-old man diagnosed with blastic plasmacytoid dendritic cell neoplasm with extensive computed tomography (CT) findings and provide an imaging focused review of this uncommon malignancy.

Blastic plasmacytoid dendritic cell neoplasm: A case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive tumor, which frequently presents as cutaneous lesions and subsequently progresses to bone marrow (BM) involvement and leukemic dissemination. BPDCN is a rare entity that belongs in the same class as acute myeloid leukemia-associated precursor neoplasms, according to the 2008 World Health Organization classification. The present study reported the case of a 26-year-old female who presented with evident thrombocytopenia, leukocytosis and anemia, but without skin lesions. The results of peripheral blood, BM smear and BM biopsy examinations detected numerous blastic or abnormal cells. In addition, flow cytometric analysis of BM demonstrated the presence of plasmacytoid dendritic cell-neoplastic precursor cells (CD4+, CD56+, CD123+, CD304+ and human leukocyte antigen-DR+ phenotype).

Plasmacytoid dendritic cell role in cutaneous malignancies

Plasmacytoid dendritic cells (pDCs) correspond to a specialized dendritic cell population that exhibit plasma cell morphology, express CD4, CD123, HLA-DR, blood-derived dendritic cell antigen-2 (BDCA-2), and Toll-like receptor (TLR)7 and TLR9 within endosomal compartments. Through their production of type I interferons (IFNs) and other pro-inflammatory cytokines, pDCs provide anti-viral resistance and link the innate and adaptive immunity by controlling the function of myeloid DCs, lymphocytes, and natural killer (NK) cells. While lacking from normal skin, pDCs are usually recruited to the skin in several cutaneous pathologies where they appear to be involved in the pathogenesis of several infectious, inflammatory/autoimmune, and neoplastic entities. Among the latter group, pDCs have the potential to induce anti-tumour immunity; however, the complex interaction of pDCs with tumor cells and their micro-environment appears to contribute to immunologic tolerance. In this review, we aim at highlighting the role played by pDCs in cutaneous malignancies with special emphasis on the underlying mechanisms.

The progression of CD56+ myeloid sarcoma: A case report and literature review

The current study presents a case of cluster of differentiation (CD)56+ myeloid sarcoma in a patient that initially presented with skin lesions, and provides evidence for the clinical and differential diagnosis of myeloid sarcoma. The patient of the present case report was a 65-year-old man who was admitted to hospital with a six-month history of bilateral purple-red papules and nodules, which were present on the upper limbs of the patient and had spread over his whole body one month prior to admission to the hospital. Pathological examination demonstrated a diffuse infusion of primitive round cells at the papillary dermis and subcutaneous tissues. The infiltrated cells were 40-60 µm in diameter and morphologically identical. Immunohistochemical examination revealed that the cells expressed myeloperoxidase, CD56, CD43 and T-cell intracytoplasmic antigen. In addition, several cells expressed CD34, and 90% of the cells expressed Ki67. While the majority of cells in myeloid sarcoma do not express CD56, the present case was a myeloid sarcoma that expressed CD56, which is extremely rare. The sarcoma in the present patient progressed rapidly, and the patient died eight months following the onset of disease. Clinicians should be aware of CD56+ myeloid sarcoma, which is easily misdiagnosed and inappropriately treated. Consequently, myeloid sarcoma may have a high malignancy and poor outcome for patients.

Blastic Plasmacytoid Dendritic Cell Neoplasm: Analysis of Clinicopathological Feature and Treatment Outcome of Seven Cases

BACKGROUND

Blastic plasmacytoid dendritic cell neoplasm (BPDCN), which is derived from the precursor of plasmacytoid dendritic cells, is a rare and highly aggressive hematologic malignancy. It has only recently been recognized as a distinct entity. BPDCN characteristically has a predilection for cutaneous involvement.

OBJECTIVE

The aim of this study was to describe the clinical and pathological features of BPDCN, and to review the treatment courses to analyze the prognosis and the optimal therapeutic approach.

METHODS

We retrospectively reviewed seven BPDCN cases registered in the Samsung Medical Center database between January 2010 and December 2014.

RESULTS

The median age of the patients was 52 years (range, 18~79 years), and six patients were male. The clinical staging was as follows: skin (n=5), lymph node (n=6), bone marrow (n=4), and peripheral blood (n=2). The skin manifestations were bruise-like tumefaction (n=4), erythematous nodule (n=4), or multiple erythematous papules (n=1). The pathological evaluation revealed dense diffuse or nodular infiltration of neoplastic cells, which were positive for CD4, CD56, and CD123 in the immunohistochemical analysis. Six patients received multiagent chemotherapy as the first-line treatment, alone (n=4), or followed by stem cell transplantation (SCT, n=1) or concurrent radiotherapy (n=1). The median progression-free survival after the first-line treatment was 6 months (range, 2~12 months).

CONCLUSION

Three different skin manifestations were observed, with pathological features analogous to each other. All patients who received chemotherapy without SCT achieved partial or complete response but experienced relapse. Furthermore, they showed various clinical courses irrelevant to the cutaneous involvement.

Human dendritic cell subsets and function in health and disease

The method of choice for the development of new vaccines is to target distinct dendritic cell subsets with antigen in vivo and to harness their function in situ to enhance cell-mediated immunity or induce tolerance to specific antigens. The innate functions of dendritic cells themselves may also be targeted by inhibitors or activators that would target a specific function such as interferon production, potentially important in autoimmune disease and chronic viral infections. Importantly targeting dendritic cells requires detailed knowledge of both the surface phenotype and function of each dendritic cell subset, including how they may respond to different types of vaccine adjuvants, their ability to produce soluble mediators and to process and present antigens and induce priming of naïve T cells. This review summarizes our knowledge of the functional attributes of the human dendritic cell subsets in the steady state and upon activation and their roles in human disease.

Blastic plasmacytoid dendritic cell neoplasm: A case report

Blastic plasmacytoid dendritic cell neoplasm (BPDCN), formerly known as agranular cluster of differentiation (CD)4+/CD56+ hematodermic neoplasm, is a rare and aggressive type of lymphoma, with only ~100 cases reported worldwide. BPDCN is a hematological malignancy derived from precursors of plasmacytoid dendritic cells and is clinically characterized by cutaneous manifestations involving the lymph nodes and peripheral blood, a leukemia-like dissemination and a poor prognosis. The present study reports the case of a 54-year-old male who presented with symptoms characteristic of BPDCN. Pathological and immunohistochemical analysis of abdominal skin lesion biopsies were used to determine a diagnosis of stage IIIE BPDCN. Although cyclophosphamide, doxorubicin, vincristine and prednisolone chemotherapy was administered, the patient succumbed to BPDCN nine days after the discontinuation of chemotherapy. Thus, the period from BPDCN presentation to mortality was ≤3 months. The case reported in the present study was characterized by rapid development and poor prognosis, and displayed additional features of BPDCN, including systemic dissemination and a short survival period.

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

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a distinct and rare neoplastic entity and was classified as a subgroup of acute myeloblastic leukemia by the WHO in 2008. The median survival of patients was 15.2 months in a large case series. Allogeneic or autologous bone marrow transplantation has been recommended by some reports because of the disease's poor prognosis. We present three patients who presented with both skin and bone marrow infiltration. A 57-year-old man, a 62-year-old woman, a 64-year-old man were admitted to our outpatient clinic because of skin lesions. All of the patient's had bone marrow infiltration with positivity of the CD4, CD56, and CD123 staining. Survival of the patient's were 42, 6 and 12 months, respectively. Two of the patients who presented as blastic form didn't respond to any chemotherapy. BPDCN is a difficult disease to diagnosis and manage. CD4, CD56, CD123, CD303, and T cell leukemia/lymphoma 1. Cutaneous lesions can present as isolated nodules, macules, and disseminated macules and nodules. Positivities are crucial to the diagnosis of the disease in histological examination. Bone marrow infiltration or disease relapse at presentation were related to poor prognosis. Complete immunocytochemical staining must be performed for all patients who have cutaneous lesions with or without blood count abnormalities. Bone marrow (allogeneic or autologous) transplantation should be considered at the first remission.