Tumeur à cellules plasmocytoïdes dendritiques blastiques révélée par des lésions ecchymotiques du visage

BPDCN is a rare malignant blood dyscrasia. It is distinguished by inaugural skin involvement, with systemic manifestations occurring much later. Histopathological examination of a skin biopsy with immunostaining establishes the diagnosis. In terms of phenotype, the tumor population is highly characteristic. The cells are negative for antigens of T- and B- cell lines. However, these cells express CD4, CD56 and TCL1, which are markers of plasmacytoid dendritic cells. The disease carries a poor prognosis and evolves in the short to middle term in the same way as acute leukemia. First-line treatment consists of the chemotherapy regimens used in aggressive lymphoma or acute leukemia. A bone marrow graft is sometimes performed at the time of initial relapse. Average survival is 12 months for chemotherapy alone and 30 months for transplant after first relapse. Early bone marrow transplantation has been shown to improve survival.