title: A peculiar case of acute myeloid leukemia mimicking plasmacytoid dendritic precursor cell leukemia.
abstract: Differential diagnosis between plasmacytoid dendritic precursor cell leukemia (pDC leukemia) and acute myeloid leukemia (AML) with monocytic differentiation is difficult due to shared clinicopathological features ; however, such diagnosis is critical because the two leukemias are treated differently. Here we report a peculiar case of AML mimicking pDC leukemia. A 22-year-old man presented with leukocytopenia and bone marrow involvement of atypical plasmacytoid cells with a prominent nucleolus. In spite of positive cytochemical staining for NaF-sensitive naphthyl butyrate esterase, this case was diagnosed as pDC leukemia because the abnormal cells were positive for CD4, CD56, and CD123, and negative for myeloperoxidase and lysozyme. The patient achieved complete remission after 4 courses of combination chemotherapy, but relapsed four months later with leukemic manifestation and skin involvement. The morphology of the leukemia cells became myelomonoblastic, and some were immunohistochemically positive for lysozyme, suggesting AML. Although the patient received allogenic stem cell transplantation twice, he died of progressive disease. This case demonstrates the importance of cytochemical staining for naphthyl butyrate esterase in differential diagnosis between AML and pDC leukemia coexpressing CD4, CD56, and CD123.
authors.affiliation: Division of Hematology, Department of Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Sano
authors.forename: Taizo
authors.initials: T
authors.lastname: Tasaka
authors.forename: Hirotake
authors.initials: H
authors.lastname: Nishimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Akiyama
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kubo
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Matsuhashi
authors.forename: Hideho
authors.initials: H
authors.lastname: Wada
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugihara
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Yamakawa
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Sadahira
mesh_terms: D000208:Acute Disease; D000328:Adult; D015703:Antigens, CD / Q000096:biosynthesis; D001854:Bone Marrow Cells / Q000473:pathology; D002265:Carboxylic Ester Hydrolases / Q000032:analysis; D003713:Dendritic Cells / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D007951:Leukemia, Myeloid / Q000175:diagnosis* / Q000201:enzymology / Q000473:pathology; D007952:Leukemia, Plasma Cell / Q000175:diagnosis* / Q000201:enzymology / Q000473:pathology; D008297:Male; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D002265:Carboxylic Ester Hydrolases; C021855:naphthylbutyrate esterase