Clinical Features Of CD5-negative Small B-cell Lymphoma

ObjectiveTo investigate the clinical features of diseases included in CD5 small B-cell lymphoma(SBCL) and the characteristics of presumptive spleen marginal zone lymphoma(SMZL), which were included in unclassifiable CD5"SBCL in our study.MethodsClinical presentation and laboratory findings from 211 patients of CD5-SBCL seen at our hostipal between 2003 to 2009 were retrospectively analyzed, and the results were compared with that in other studies.ResultsAmone the 211 patients, the diagnoses included hairy-cell leukaemia(HCL, n=23), lymphoplasmacytic lymphoma(LPL, n=52), follicular lymphoma(FL, n=25), marginal zone lymphoma(MZL, n=32) and CD5"SBCL, unclassifiable(n=79). Secondnary bone marrow fibrosis was less common in Chinese HCL and a positive result of tartrate-resistant acid phonphatase(TRAP) could not distinguish HCL from spleen lymphoma in which the acitivity of TRAP might also be strong. Lytic bone lesions were seen in 21.9%of LPL, but the degree of these lessions was usually slight. The median age of the FL patients in our study was low and 53.8% of the grade 1,2 cases had a ki-67>20%. Most SMZL cases expressed CD22, FMC7 and CDllc, but only 30.8% of the cases were positive for slgM expression. HBV infection was common and seen in 26.7% of SMZL cases. A group of cases named as presumptive SMZL were picked out from the unclassifiable CD5"SBCL and were respectively compared with the "true" SMZL and the remanent unclassifiable CD5-SBCL cases. Presumptive SMZL and the "true" SMZL were similar in clinical features and flow cytometric immunophenotype, and the expression of CD25 were all lower than that in remanent unclassifiable CD5-SBCL. Nonetheless, it was still inadequate to confirm the diagnosis of SMZL based on the clinical features only.ConclusionSecondnary bone marrow fibrosis was less common in Chinese HCL and a positive result of TRAP could not distinguish HCL from spleen lymphoma. Lytic bone lesions were seen in 1/5 of LPL. Patients of FL had lower ages and more than half of the cases with low grade FL had a high proliferation fraction.The expression rate of slgM was low and the infection rate of HBV was high in SMZL. It was difficult to confirm the diagnosis of SMZL without a spleen specimen.