title: De novo CD5+ Burkitt lymphoma/leukemia.
abstract: CD5 is a T-cell marker aberrantly expressed in B-cell chronic lymphocytic leukemia and mantle cell lymphoma. Other B-cell neoplasms, including Burkitt lymphoma, are usually CD5-. We report 4 cases of de novo CD5+ Burkitt lymphoma/leukemia in elderly patients, all of whom were in a leukemic phase and had variable lymph node and splenic involvement. The blasts were typically medium sized, with folded nuclei, distinct but not prominent nucleoli, and moderate amounts of somewhat vacuolated basophilic cytoplasm; they were terminal deoxynucleotidyl transferase--negative and surface immunoglobulin--positive. All 4 cases demonstrated c-myc rearrangement, but none had t(14;18), t(11;14), or cyclin D1 overexpression or rearrangement. Only 1 patient achieved complete remission after hyper-CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone) therapy. One patient responded poorly to hyper-CVAD, and 2 patients died during induction chemotherapy. These rare cases of aggressive lymphoid malignancy with CD5 positivity and molecular features associated with Burkitt lymphoma/leukemia are best classified as Burkitt leukemia. However, the morphologic and immunophenotypic similarity to the blastoid variant of mantle cell lymphoma are diagnostically challenging. The diseases can be distinguished at the genetic level, since Burkitt lymphoma involves the rearrangement of c-myc, and mantle cell lymphoma usually the overexpression or rearrangement of cyclin D1.
authors.affiliation: Department of Laboratory Medicine, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: O'Brien
authors.forename: J
authors.initials: J
authors.lastname: Faber
authors.forename: T
authors.initials: T
authors.lastname: Manshouri
authors.forename: J
authors.initials: J
authors.lastname: Romaguera
authors.forename: Y O
authors.initials: YO
authors.lastname: Huh
authors.forename: H
authors.initials: H
authors.lastname: Kantarjian
authors.forename: M
authors.initials: M
authors.lastname: Keating
authors.forename: M
authors.initials: M
authors.lastname: Albitar
mesh_terms: D000368:Aged; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D002051:Burkitt Lymphoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D018956:CD5 Antigens / Q000032:analysis*; D002466:Cell Nucleolus / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology; D003593:Cytoplasm / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D016259:Genes, myc / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D007958:Leukocyte Count; D008198:Lymph Nodes / Q000473:pathology; D020522:Lymphoma, Mantle-Cell; D008297:Male; D008875:Middle Aged; D013154:Spleen / Q000473:pathology
chemical_list: D018956:CD5 Antigens