Leukemic Manifestation of Blastic Plasmacytoid Dendritic Cell Neoplasm Lacking Skin Lesion : A Borderline Case between Acute Monocytic Leukemia

摘要

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with a poor prognosis. We encountered a unique case of BPDCN that was leukemic at presentation without skin lesion and expressed CD33 antigen. A 74-year-old man was admitted because of dyspnea. Physically, hepatosplenomegaly, but not skin lesions and superficial lymph node swelling, was noted. The white blood count was 33.6 × 10⁹/L with 19% giant abnormal cells. These cells were positive for CD4, CD86, CD123 (bright), BDCA-2, and HLA-DR, but negative for CD1a, CD3, CD11b, CD11c, CD13, CD14, CD19, CD64, and CD68. From these findings, a diagnosis of BPDCN was made. In terms of unusual expression, these tumor cells were positive for CD33 but negative for CD56. The karyotype was 47, XY, t(6;8) (p21;q24), + r. We performed combination chemotherapy (Ara-C + VP-16 + MIT), which resulted in a marked reduction of tumor cells and improvement of the dyspnea. On day 16, however, he died of sepsis due to Bacillus cereus . The clinical picture of this patient is unusual and may provide new information on the clinicopathology of BPDCN. [ J Clin Exp Hematopathol 52( 2) : 107-111, 2012 ]