title: Neoplasms derived from plasmacytoid dendritic cells.
abstract: Plasmacytoid dendritic cell neoplasms manifest in two clinically and pathologically distinct forms. The first variant is represented by nodular aggregates of clonally expanded plasmacytoid dendritic cells found in lymph nodes, skin, and bone marrow ('Mature plasmacytoid dendritic cells proliferation associated with myeloid neoplasms'). This entity is rare, although likely underestimated in incidence, and affects predominantly males. Almost invariably, it is associated with a myeloid neoplasm such as chronic myelomonocytic leukemia or other myeloid proliferations with monocytic differentiation. The concurrent myeloid neoplasm dominates the clinical pictures and guides treatment. The prognosis is usually dismal, but reflects the evolution of the associated myeloid leukemia rather than progressive expansion of plasmacytoid dendritic cells. A second form of plasmacytoid dendritic cells tumor has been recently reported and described as 'blastic plasmacytoid dendritic cell neoplasm'. In this tumor, which is characterized by a distinctive cutaneous and bone marrow tropism, proliferating cells derive from immediate CD4(+)CD56(+) precursors of plasmacytoid dendritic cells. The diagnosis of this form can be easily accomplished by immunohistochemistry, using a panel of plasmacytoid dendritic cells markers. The clinical course of blastic plasmacytoid dendritic cell neoplasm is characterized by a rapid progression to systemic disease via hematogenous dissemination. The genomic landscape of this entity is currently under intense investigation. Recurrent somatic mutations have been uncovered in different genes, a finding that may open important perspectives for precision medicine also for this rare, but highly aggressive leukemia.
authors.affiliation: Section of Pathology, Department of Molecular and Translational Medicine, Spedali Civili, University of Brescia, Brescia, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Facchetti
authors.affiliation: Section of Pathology, Department of Molecular and Translational Medicine, Spedali Civili, University of Brescia, Brescia, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Cigognetti
authors.affiliation: Section of Pathology, Department of Molecular and Translational Medicine, Spedali Civili, University of Brescia, Brescia, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Fisogni
authors.affiliation: Department of Hematology, Spedali Civili, Brescia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rossi
authors.affiliation: Section of Pathology, Department of Molecular and Translational Medicine, Spedali Civili, University of Brescia, Brescia, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lonardi
authors.affiliation: Section of Pathology, Department of Molecular and Translational Medicine, Spedali Civili, University of Brescia, Brescia, Italy.
authors.forename: William
authors.initials: W
authors.lastname: Vermi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D001706:Biopsy; D002454:Cell Differentiation; D019070:Cell Lineage; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000737:chemistry / Q000276:immunology / Q000473:pathology*; D020022:Genetic Predisposition to Disease; D019337:Hematologic Neoplasms / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000473:pathology* / Q000628:therapy; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D009154:Mutation; D010641:Phenotype; D011237:Predictive Value of Tests; D011379:Prognosis; D012878:Skin Neoplasms / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000473:pathology* / Q000628:therapy
chemical_list: D014408:Biomarkers, Tumor