Introduction: Plasmacytoid dendritic cell leukemia is a rare subtype of acute leukemia, which has recently been established as a distinct pathologic entity that typically follows a highly aggressive clinical course in adults. The aim of this report is to present a case of plasmacytoid dendritic cell leukemia due to its rarity and difficulty to recognize and diagnose it.
Case report: We present a case of a 67 year-old man who presented multiple subcutaneous lesions on his face, neck, chest and upper extremities with reddish-brown, brown colour. In the bone marrow aspirate 83% of the blast cells were found. Immunophenotypically the blasts were positive for CD4, CD56, CD123 (high intensity), CD36, CD22, CD10 (10.42%), CD33, HLA-DR, CD7 (9.24%), CD38 (34.8%) and negative for CD13, CD64, CD14, CD16, CD15, CD11b, CD11c, CD3, CD5, CD2, CD8, CD19, CD20, CD34. The skin biopsy showed lymphohistiocytoid infiltration in the dermis. The patient was diagnosed with acute plasmacytoid dendritic cell leukemia and received polychemotherapy with rapid response of skin lesions and blastic infiltration of the bone marrow. After 3 courses of polychemotherapy the cutaneous lesions reappeared and multiplied. The blast infiltration in the bone marrow increased to 70%. A more aggressive polychemotherapy regimen was administered, but the patient presented serious complications (febrile neutropenia) and died in septic shock 8 months after the initiation of treatment.
Conclusions: Immunophenotyping of blasts cells is indispensable in the diagnosis of plasmacytoid dendritic cell leukemia. The CD4+, CD56+, lin-, CD123 ++high, CD11c-, CD36+, HLA-DR+, CD34-, CD45+ low profile is highly suggestive for pDCL. The outcome of plasmacytoid dendritic cell leukemia is poor. Despite the high rate of initial response to treatment, early relapses occur and the patients die of disease progression.