title: Hairy cell leukemia variant: fact or fiction.
abstract: Hairy cell leukemia variant (HCL-V) is a poorly described, rare B-cell lymphoproliferative disorder typically positive for CD103 and CD11c, while lacking CD25. Splenic marginal zone lymphomas (SMZL) also have this unusual phenotype in 15% to 25% of cases, have other overlapping clinical or morphologic features, and are more common than HCL-V. The purpose of our study was to better characterize HCL-V and determine whether most cases could be distinguished from SMZL. Cases with an HCL-V phenotype were identified from our flow cytometry service, and 10 were selected for further study based on bone marrow or splenic tissue availability. All cases had cytologic features consistent with HCL-V, and 9 of 10 patients had lymphocytosis. Bone marrow involvement was mostly interstitial and/or sinusoidal without lymphoid nodules. Coexpression of preswitched with postswitched heavy chain isotypes, an unusual feature of HCL, was seen in 2 of 4 cases. This study better defines HCL-V and establishes that most cases do not represent SMZL.
authors.affiliation: Department of Pathology, University of Utah, Salt Lake City, 84132, USA.
authors.forename: Melissa H
authors.initials: MH
authors.lastname: Cessna
authors.forename: Leah
authors.initials: L
authors.lastname: Hartung
authors.forename: Sheryl
authors.initials: S
authors.lastname: Tripp
authors.forename: Sherrie L
authors.initials: SL
authors.lastname: Perkins
authors.forename: David W
authors.initials: DW
authors.lastname: Bahler
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D039521:CD11c Antigen / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D039001:Integrin alpha Chains / Q000032:analysis; D037102:Lectins / Q000032:analysis; D007943:Leukemia, Hairy Cell / Q000145:classification / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D051918:Sialic Acid Binding Ig-like Lectin 2
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D039521:CD11c Antigen; C497867:CD22 protein, human; D015815:Cell Adhesion Molecules; D039001:Integrin alpha Chains; D037102:Lectins; D051918:Sialic Acid Binding Ig-like Lectin 2; C091367:alpha E integrins