Indispensable role of immunophenotyping in diagnosing leukemic phase of blastic plasmacytoid dendritic cell neoplasm without cutaneous manifestation

Blastic plasmacytoid dendritic cell neoplasm usually presents as skin lesions. Diagnostic error occurs when it primarily presents in leukemic phase without skin involvement. Triad of CD4, CD56 and CD123 immunophenotype expression is essential to avoid misdiagnosis of this rare hematological malignancy. Here we describe a patient who presented in overt leukemic phase of BPDCN highlighting diagnostic challenges encountered that resulted in delayed diagnosis and poor outcome.