title: CD5-positive B-cell neoplasms of indeterminate immunophenotype: a clinicopathologic analysis of 26 cases.
abstract: The flow cytometric classification of CD5-positive small B-cell neoplasms is dependent largely on the differential expression of CD23 and FMC-7. Occasional CD5-positive neoplasms with prominent co-expression of these antigens are encountered, precluding definitive immunophenotypic classification. The authors studied the clinicopathologic features of 26 neoplasms with this indeterminate immunophenotype. Available morphologic material was reviewed and analysis of CYCLIN D1 derangement was performed in selected cases by a combination of immunohistochemical, molecular, and cytogenetic techniques. Individual neoplasms were classified based on correlation of morphologic features and results of CYCLIN D1 studies. The neoplasms were classified into five categories: chronic lymphocytic leukemia (14 cases), "favor chronic lymphocytic leukemia" (3 cases), mantle cell lymphoma (3 cases), lymphoplasmacytic lymphoma (1 case), and unclassifiable (5 cases). Three of the unclassifiable neoplasms had morphologic features of mantle cell lymphoma, but CYCLIN D1 derangement could not be demonstrated. Neither relative expression of CD23 and FMC-7 nor intensity of CD20 or surface immunoglobulin expression was helpful in final classification. The authors conclude that CD5-positive small B-cell neoplasms with an indeterminate immunophenotype are a heterogeneous group, requiring additional studies for final classification. The majority (65%) appear to be chronic lymphocytic leukemia, with most of the remaining cases either definitively mantle cell lymphoma or unclassifiable.
authors.affiliation: Department of Pathology, Hematopathology Division, University of Texas Southwestern Medical Center, Dallas, 75390, USA.
authors.forename: Sheryl L
authors.initials: SL
authors.lastname: Asplund
authors.forename: Robert W
authors.initials: RW
authors.lastname: McKenna
authors.forename: Jeff E
authors.initials: JE
authors.lastname: Doolittle
authors.forename: Steven H
authors.initials: SH
authors.lastname: Kroft
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D018956:CD5 Antigens / Q000096:biosynthesis*; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000145:classification / Q000276:immunology* / Q000473:pathology*; D020522:Lymphoma, Mantle-Cell / Q000145:classification / Q000276:immunology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D017455:Receptors, IgE / Q000096:biosynthesis; D012189:Retrospective Studies
chemical_list: D000951:Antigens, Neoplasm; D018956:CD5 Antigens; D006023:Glycoproteins; C112523:MS4A1 protein, human; D017455:Receptors, IgE