Neoplasia hematodérmica CD4+/CD56+. Diagnóstico histopatológico, fisiopatología y avances recientes de un tumor originado en células dendríticas plasmocitoides

CD4+/CD56+ Hematodermic Neoplasm is an uncommon tumor found in the adult population and generally evolves with a poor clinical outcome. The presence of cutaneous involvement at the beginning of the disease, followed by an extracutaneous generalized phase is characteristic. Histologically, the CD4+/CD56+ Hematodermic Neoplasm features a nonepidermotropic, dermal and subdermal infiltration of cells which resemble lymphoblasts or myeloblasts. The CD4+/CD56+ immunophenotype not only is characteristic, but also a very important tool in the differential diagnosis between other cutaneous lymphoid/myeloid neoplasms. Recently, the hematopoietic-derived plasmacytoid dendritic cell has been related to the CD4+/CD56+ hematodermic neoplasm origin. Typically, the plasmacytoid dendritic cells express the surface marker IL-3 receptor α (CD123) and lack of myeloid and lymphoid antigens. Functionally, plasmacytoid dendritic cells are implicated in the regulation of innate and adaptive cell immunity, antigen processing, production of inflammatory cytokines and probably, the association with lymphoid-organ tolerogenic responses. Understanding plasmacytoid dendritic cell dysfunction is important for its implication in several pathologic conditions such as autoimmune disorders, viral infections and loss of tolerance response in some tumors.