CD4+/CD56+ Hematodermic Tumor

Abstract

Described herein is the evolution in the diagnosis and classification of tumors that are variously known as blastic or blastoid natural killer cell lymphoma, CD4+/CD56+ hematodermic neoplasm, or tumors of plasmacytoid dendritic cell lineage. As illustrated by cases submitted to the 2005 Society for Hematopathology/European Association for Haematopathology Workshop, these tumors display a range of clinical manifestations and various morphologic and immunophenotypic features. Recent evidence suggests a close histogenetic relationship for most cases to plasmacytoid dendritic cells. We outline the typical presenting features and the clinical course of CD4+/CD56+ hematodermic tumors, including leukemic relapses with shifts to myelomonocytic differentiation. The currently unresolved issues are largely related to the limits of this entity, particularly the relationship to myeloid leukemia and undifferentiated blastic neoplasms, with which there is diagnostic overlap. Although questions remain, delineation of the CD4+/CD56+ hematodermic tumor and its improved recognition has already served as a catalyst toward better understanding of the multilineage potential of hematopoietic malignancies.

Blastic Plasmacytoid Dendritic Cell Neoplasm: Cytopathologic Findings

“…Its previous names, which include blastic NK cell lymphoma, agranular CD4+ natural killer cell leukemia, and CD4+/CD56+ hematodermic neoplasm, reflect the evolving understanding of the disease entity [1,2]. Currently, it is well accepted that BPDCN represents a unique hematopoietic neoplasm arising from precursors of plasmacytoid dendritic cells (PDCs) [3,4,5,6,7].…”

“…BPDCN is highly aggressive with a clinical presentation characterized by early skin involvement and rapid dissemination. Relapse after multiagent chemotherapy is common, and the median overall survival is around 12–14 months [1,2,7]. Most patients are elderly, with a median age of 61–71 years, although patients of any age can be afflicted [2,8,9,10].…”

“…Relapse after multiagent chemotherapy is common, and the median overall survival is around 12–14 months [1,2,7]. Most patients are elderly, with a median age of 61–71 years, although patients of any age can be afflicted [2,8,9,10]. The male/female ratio is 2–7:1 [7,8].…”

“…The male/female ratio is 2–7:1 [7,8]. Phenotypically, cells of BPDCN are often positive for CD4, CD56, CD123, and CD45 and are consistently negative for Epstein-Barr virus [1,2,10]. The cytological features of BPDCN have been previously described [2,9] in peripheral blood and bone marrow aspirates.…”

“…Phenotypically, cells of BPDCN are often positive for CD4, CD56, CD123, and CD45 and are consistently negative for Epstein-Barr virus [1,2,10]. The cytological features of BPDCN have been previously described [2,9] in peripheral blood and bone marrow aspirates. However, to the best of our knowledge, the cerebrospinal fluid (CSF) cytology of BPDCN has not been reported previously.…”