Blastic plasmacytoid dendritic cell neoplasm presenting as leukemia without cutaneous involvement in a 25 years male patient: Unusual presentation of a rare entity.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive neoplasm classified under "acute myeloid leukemia (AML) and related precursor neoplasm" by current WHO classification. Elderly male are commonly affected with cutaneous lesion being the hallmark of disease presentation. The disease progresses rapidly and sooner or later involves bone marrow and peripheral blood. Cases presenting primarily as leukemia without cutaneous involvement is a rarity with about 29 cases reported in literature till date. Characteristic immunophenotype of CD4 + /CD56 +/- cells expressing antigens associated with plasmacytoid dendritic cells like CD123, TCL1, BDCA2/CD303, cutaneous lymphocyte-associated and interferon dependent molecule MxA, in absence of any other lineage specific marker confirms the diagnosis. The disease has a poor survival and no standardized therapeutic strategy in the current scenario. A case of 25-year-male presenting with leukemic BPDCN without cutaneous involvement is presented here, who was treated with AML like protocol followed by hematopoietic stem cell transplantation, but succumbed to the disease within 8 months of diagnosis. The present case is being first to be reported from India.