[CD5+ CD10+ extranodal B-cell lymphoma with tetraploid chromosomal abnormality]

An 84-year-old man was admitted with pleural lymphomatous effusion and bone marrow infiltration. The abnormal cells from the effusion showed abundant basophilic cytoplasm, large atypical nuclei, and small nucleoli with frequent mitosis. The abnormal cells were found to be CD5+, CD10+, CD19+, and CD20+ by flow cytometry, and had clonal rearrangements of the IgH-JH gene, indicating the existence of a clonal B-cell population. No bcl-1, bcl-2, bcl-6, or c-myc rearrangement was found. Neither human herpesvirus 8 (HHV-8) nor Epstein-Barr virus was detected in the abnormal cells. Tetraploid chromosomal abnormality was present. After administration of prednisolone, transient disappearance of the effusion was obtained.