Blastic Plasmacytoid Dendritic Cell Neoplasm With De Novo TET2 and KDM6A Mutations.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, highly aggressive hematologic malignancy characterized by cutaneous involvement with potential dissemination to peripheral blood, bone marrow, lymph nodes, or extranodal sites. We present the first documented case of BPDCN exhibiting complex epigenetic dysregulation in a 54-year-old female who developed rapidly progressive purpuric lesions on the trunk, diagnosed via skin biopsy and immunohistochemistry. Cytogenetic analysis revealed triple molecular aberrations including a t(1;6) (p31;q25) translocation, a TET2 frameshift deletion (44.1% VAF), and a KDM6A missense mutation (c.262G>A, 46.6% VAF). The patient died within 6 months post-diagnosis, suggesting that this aggressive clinical course may be associated with a novel clinicogenetic subtype of BPDCN.