title: A case of T cell prolymphocytic leukemia involving blast transformation.
abstract: We report a case of T cell prolymphocytic leukemia (T-PLL) involving blast transformation. At the initial diagnosis, most peripheral blood cells demonstrated proliferation of indolent T cell small cell variants, i.e., small to medium prolymphocytes with inconspicuous nucleoli and a normal karyotype. These cells were positive for surface CD4, CD5, and CD7, and cytoplasmic CD3, but negative for surface CD3 and CD8 and cytoplasmic terminal deoxynucleotidyl transferase (TdT). The T cell receptor (TCR) Cβ1 gene was rearranged in the cells. Large prolymphocytes with prominent nucleoli, irregular nuclei, and cytoplasmic vacuoles that exhibited chromosome 8 trisomy were observed about 1.5 years later. The CD4+CD8- single positive effector memory T cells transformed into surface CD4+CD8+ double positive precursor T cells. The clonal TCR gene rearrangement patterns of these cells were identical throughout the clinical course, suggesting clonal blast transformation. The CD4+CD8+ cells demonstrated increased chromosome 8 trisomy combined with complex chromosome abnormalities with t(14;14)(q11.2;q32) containing a 14q32 chromosome after transformation. T cell leukemia 1a (TCL1a) (14q32.1) may be implicated in this case. The TCL1a oncoprotein is expressed in approximately 70% of T-PLL cases. The disease gradually developed resistance to chemotherapy, and the patient died of the disease. It is known that indolent T-PLL can become aggressive. Therefore, similar transformations may occur in other aggressive T-PLL cases, particularly those involving trisomy 8 and TCL1a.
authors.affiliation: Division of Hematology, Department of Internal Medicine, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. kichika@juntendo.ac.jp.|Division of Hematology, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan. kichika@juntendo.ac.jp.
authors.forename: Kunimoto
authors.initials: K
authors.lastname: Ichikawa
authors.affiliation: Division of Hematology, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Noguchi
authors.affiliation: Division of Hematology, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Imai
authors.affiliation: Division of Hematology, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan.
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Sekiguchi
authors.affiliation: Division of Hematology, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Wakabayashi
authors.affiliation: Division of Clinical Laboratory, Urayasu Hospital, Juntendo University School of Medicine, Chiba, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sawada
authors.affiliation: Division of Hematology, Department of Internal Medicine, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Komatsu
mesh_terms: D000368:Aged; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000276:immunology; D005434:Flow Cytometry; D019674:Genes, T-Cell Receptor beta / Q000235:genetics* / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D015461:Leukemia, Prolymphocytic, T-Cell / Q000235:genetics / Q000276:immunology; D008297:Male; D014314:Trisomy
chemical_list: D015703:Antigens, CD