Blastic plasmacytoid dendritic cell neoplasm: cytopathologic findings

Approval of tagraxofusp-erzs for blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and clinically challenging hematologic malignancy with dismal outcomes. With a median age of ∼70 years, the majority of patients with BPDCN have experienced historically suboptimal responses with intensive chemotherapy regimens. The major scientific breakthrough in this field was the recognition of overexpression of a surface receptor, CD123/interleukin 3 (IL-3) receptor α, in all patients. Importantly, a novel therapeutic agent consisting of a truncated diphtheria toxin (DT) payload fused to recombinant human IL-3 was being developed, one that targeted CD123, initially known as DT-IL-3 (later known as SL401; tagraxofusp; tagraxofusp-erzs [Elzonris]). The identification of this agent, and subsequent clinical trials specifically dedicated to patients with BPDCN (including a pilot study, followed by a larger phase 1/2 multicenter study [90% overall response rate [ORR] in frontline and 67% ORR in relapsed/refractory setting]), in part led to approval of tagraxofusp-erzs on 21 December 2018. Tagraxofusp-erzs was the first agent approved for BPDCN (for patients ages 2 years and older), and importantly, established this drug as the first CD123-targeted agent ever approved. The most notable toxicity of tagraxofusp-erzs is occurrence of the capillary leak syndrome, which occurs frequently at all grades, and has also been observed to be life-threatening, appropriately leading to a US Food and Drug Administration "black box" warning in the package insert. The preclinical and clinical aspects of drug development of tagraxofusp-erzs as monotherapy leading to drug approval are reviewed herein, with discussion of future directions of this novel agent, including consideration for rational combinations in BPDCN and beyond.

Cytologic features of blastic plasmacytoid dendritic cell neoplasm involving liver: A case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare but clinically aggressive hematologic malignancy, believed to originate from plasmacytoid dendritic cells (PDCs) although it possesses multilineage potentials. Due to the dismal prognosis, accurate and rapid diagnosis is critical for early management. The disease usually initially involves skin and bone marrow. Here we report the cytopathologic findings in a case of BPDCN involving the liver in a patient previously diagnosed with BPDCN from skin and lymph node biopsies. The fine-needle aspiration specimen from the liver lesion demonstrates a hypercellular smear of atypical epithelioid cells dispersed singly or in loose groups. These cells have enlarged, eccentric, round to irregular nuclei with fine chromatin. The agranular gray-blue cytoplasm shows delicate wispy cytoplasmic extensions and cytoplasmic microvacuoles. Binucleation is common. The concurrent core biopsy shows that the neoplastic plasmacytoid cells with eccentric nuclei were positive for CD4, CD7, CD43, CD56, and CD68, confirming the diagnosis of BPDCN. Mutations of ASXL1 and TET2, classic for BPDCN, and a complex karyotype were detected in skin, bone marrow, and lymph node specimens. We catalog the heterogeneous pathologic features of this rare disease, emphasizing the clinical and histopathological correlation. The differential diagnoses and review of literature are also included. Awareness of this disease and accurate diagnosis are emphasized to aid early management and potentially produce a better clinical outcome.

Blastic Plasmacytoid Dendritic Cell Neoplasm: Clinical Presentation and Diagnosis

Clinical and biological presentation of patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) is depicted to highlight criteria that might alert physicians. Diagnosis of BPDCN is still challenging and requires (1) immunophenotyping of blood or bone marrow aspiration using several markers (CD4, CD56, HLA-DR, myeloid and lymphoid lineage markers) and should include pDC markers such as CD123, cTCL1, CD303, and CD304, and/or (2) pathologic analysis of cutaneous lesions, also with immunohistochemistry using markers specific to BPDCN.

A critical review of treatment modalities for blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a clinically aggressive tumor derived from the precursors of plasmacytoid dendritic cells. It is a rare disease presenting across all ages with either skin or both skin and bone marrow involvement often conferring a poor prognosis. Though localized radiation has been used before, acute leukemia based regimens, remains the treatment of choice for induction of remission. Hematopoietic stem cell transplant, either autologous or allogeneic, is further required for attaining sustained remissions. Recently, a number of targeted therapies and newer drugs have been used as the molecular and genetic understanding of the disease have improved.

Morphologic characteristics of blastic plasmacytoid dendritic cell neoplasm: a case report

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive lymphoma derived from plasmacytoid dendritic cells or precursor dendritic cells. Despite some 240 reported cases, its morphology and especially ultrastructure has not been satisfactorily studied. A case is reported of a 13 year old boy, who, despite chemotherapy, died within a 12-month period. The electron microscopy findings - microvillous processes, nuclei with slight irregularities, a moderate amount of heterochromatin, and rough endoplasmic reticulum in the form of long, narrow profiles, often in parallel arrangements - taken together, serve to distinguish BPDCN from other neoplastic cells, such as monocytes, plasma cells and the cells of chronic lymphocyte leukemia.