Blastic NK-Cell Lymphomas (Agranular CD4+CD56+ Hematodermic Neoplasms): A Review

Abstract

Blastic natural killer (NK) cell lymphoma (also termed CD4+CD56+ hematodermic neoplasm) is a recently described entity, with the first case reported in 1994. It was suggested initially that the disease originates from NK cells. Since 1994, single cases and a few small series have been published. In this review, data from the literature and a series of 30 cases from the French and Dutch study groups on cutaneous lymphomas are discussed. The major clinical, histopathologic, and phenotypic aspects of the disease and diagnostic criteria and data suggesting a plasmacytoid dendritic cell origin for the tumor cells are provided.

Blastic plasmacytoid dendritic cell neoplasm with leukemic presentation: an Italian multicenter study

“…13,23,24 In our series cytogenetic analysis confirmed that most patients had unfavorable cytogenetics (48%), among which complex karyotype was a distinctive feature. Moreover, as recently found, 25 no patients had NPM1 mutations.…”

“…As for the therapy-related forms of BPDCN, all six affected patients received chemotherapy for the first neoplasm; the two patients with prostate cancer also received radiotherapy; the patient with a previous non-Hodgkin's lymphoma 4 years ago underwent a double autologous HSCT. The median time of latency between the first exposure to cytotoxic treatment for the primary neoplasm and the diagnosis of BPDCN was 5 years (range, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

“…9,10 Despite an initial response to systemic chemotherapy, the disease regularly relapses and the median overall survival is dismal (12-14 months). 9,12,13 The few series published so far rarely exceed 20 cases, and most of them include cases with exclusive or predominant cutaneous involvement, making it difficult to define the biological, clinical and prognostic features of the disease and, in particular, of the leukemic form.…”

Expression of the plasmacytoid dendritic cell marker BDCA-2 supports a spectrum of maturation among CD4+ CD56+ hematodermic neoplasms

“…CD4 þ CD56 þ hematodermic neoplasms [1][2][3] have been variably referred to as blastic NK-cell lymphomas, 4,5 CD56 þ blastic tumors, 6 CD4 þ CD56 þ lineage-negative malignancies, 7 blastic type 2 dendritic cell leukemia, 8 and plasmacytoid dendritic cell leukemia/lymphoma. 9 CD4 þ CD56 þ hematodermic neoplasms are characterized by presentation as extranodal masses that are often cutaneous, with eventual leukemic dissemination and a clinically aggressive course.…”

“…15 For example, variable expression of CD2, CD7, CD33, CD36, and CD68 has been demonstrated and a subset of cases display terminal deoxynucleotidyl transferase (TdT) immunoreactivity. 1,3,[16][17][18] Blood dendritic cell antigen-2 (BDCA-2) is a recently described cell-surface protein that is selectively expressed on plasmacytoid dendritic cells. 19 Primary amino-acid sequence homology suggests that BDCA-2 (CLEC4C, HECL, CD303) may act as a carbohydrate-binding protein of the C-type lectin family, although specific ligands have not been reported.…”