title: Post-allogeneic stem cell transplant extramedullary relapse of acute megakaryoblastic leukemia initially detected by elevated WT1 mRNA levels in peripheral blood.
abstract: An 18-year-old male was admitted to our hospital for fever, and was diagnosed with acute megakaryoblastic leukemia (AML M7) based on the presence of CD42a and CD61 positive myeloblasts in peripheral blood (PB). Induction chemotherapy at our hospital resulted in complete remission (CR). Subsequently, he underwent unrelated HLA-DR one locus-mismatched allogeneic bone marrow (BM) transplantation. Although CR was maintained without development of graft-versus-host disease (GvHD), the WT1 mRNA level in PB was elevated on post-transplant day 134. As BM aspiration performed 1 week later confirmed maintenance of CR, and because the WT1 mRNA level in BM was not high in comparison with PB, we suspected extramedullary relapse. PET-CT demonstrated a thymic tumor and a gastric tumor with abnormal accumulation of FDG, and biopsy confirmed both to be extramedullary relapse of AML M7. Induction chemotherapy following local radiation therapy achieved a second CR, following which he received HLA haploidentical peripheral blood stem cell transplantation on day 256 after the first transplant. The patient is currently surviving free from both relapse and GvHD. High WT1 mRNA levels in PB as compared with BM should raise suspicion of extramedullary relapse, and PET-CT is very useful for whole body evaluation in such cases.
authors.affiliation: Department of Hematology, Hiroshima Red Cross Hospital & Atomic-bomb Survivors Hospital.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ochi
authors.forename: Koji
authors.initials: K
authors.lastname: Iwato
authors.forename: Yuta
authors.initials: Y
authors.lastname: Katayama
authors.forename: Kayo
authors.initials: K
authors.lastname: Toishigawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Okatani
authors.forename: Ryota
authors.initials: R
authors.lastname: Imanaka
authors.forename: Kohei
authors.initials: K
authors.lastname: Kyo
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Itagaki
authors.forename: Shinnya
authors.initials: S
authors.lastname: Katsutani
authors.forename: Hideki
authors.initials: H
authors.lastname: Asaoku
authors.forename: Taiichi
authors.initials: T
authors.lastname: Kyo
mesh_terms: D000293:Adolescent; D016026:Bone Marrow Transplantation; D016162:Genes, Wilms Tumor; D006801:Humans; D007947:Leukemia, Megakaryoblastic, Acute / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D008297:Male; D036102:Peripheral Blood Stem Cell Transplantation; D000072078:Positron Emission Tomography Computed Tomography; D012333:RNA, Messenger / Q000097:blood* / Q000235:genetics; D012008:Recurrence; D014184:Transplantation, Homologous
chemical_list: D012333:RNA, Messenger