title: [Lineage switch on recurrence from minimally differentiated acute leukemia (M0) to acute megakaryocytic leukemia (M7)].
abstract: Phenotypic switch in acute leukemia is a rare phenomenon. We report on a female infant with minimally differentiated acute leukemia (M 0) which underwent a lineage switch on relapse. In March 1997, a 1-year-8-month old girl was admitted to our hospital with a high-grade fever and generalized purpura. Bone marrow showed 84% blasts. The blasts were negative for peroxidase, periodic acid-Schiff and alpha-naphthyl butyrate esterase. Immunophenotypic analyses of the blast cells were positive for CD 13, CD 33 antigens, as well as CD 34. Lymphoid markers all were negative. Though some blasts morphologically demonstrated cytoplasmic blebs, CD 41 was negative and ultrastructural platelet peroxidase was absent. Based on these hematological features, the patient was diagnosed as having AML-M 0. She was treated according to the Children's Cancer and Leukemia Study Group schedule and a complete remission was achieved 1.5 months after starting induction therapy. However, she relapsed in spite of continued chemotherapy in July 1997, when the cytomorphological pattern changed and the patient was diagnosed both morphologically and immunologically as having M 7. Electron microscopy revealed platelet peroxidase (+) and CD 41 (+). Cytogenetic studies on relapse demonstrated inv(3) (q 21 p 25). We attempted aggressive reinduction therapy, but without effect. The patient simultaneously developed severe pneumonia and died in February, 1998. A lineage switch on relapse and resistance to chemotherapy may be associated with the occurrence of genetic aberration.
authors.affiliation: Department of Pediatrics, Sapporo National Hospital.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hatae
authors.forename: Kazuyori
authors.initials: K
authors.lastname: Yagyu
authors.forename: Noriko
authors.initials: N
authors.lastname: Yanazume
authors.forename: Yuuko
authors.initials: Y
authors.lastname: Chou
authors.forename: Susumu
authors.initials: S
authors.lastname: Iizuka
authors.forename: Takeo
authors.initials: T
authors.lastname: Takeda
authors.forename: Takaaki
authors.initials: T
authors.lastname: Shikano
authors.forename: Mitsuoki
authors.initials: M
authors.lastname: Eguchi
mesh_terms: D000208:Acute Disease; D019070:Cell Lineage; D005260:Female; D006801:Humans; D007223:Infant; D007938:Leukemia / Q000473:pathology*; D007947:Leukemia, Megakaryoblastic, Acute / Q000473:pathology*; D012008:Recurrence