PRIMARY CENTRAL-NERVOUS-SYSTEM LYMPHOMAS - IMMUNOPHENOTYPIC, VIROLOGICAL, AND CYTOGENETIC FINDINGS OF 3 PATIENTS WITHOUT IMMUNE DEFECTS

Background. Primary central nervous system (PCNS) lymphoma is a relati vely rare disease, but an increasing incidence is reported. The Epstei n-Barr virus (EBV), which is often found in lymphomas of immunocomprom ised patients, has been implicated in the development of lymphomas. Ma ny cytogenetic analyses of nodal B cell lymphomas have been performed, but few studies on PCNs lymphomas have been reported. Methods. The de tection of EBV genome using the polymerase chain reaction (PCR) method and cytogenetic studies were performed, in addition to histopathologi c and immunophenotypic approaches in biopsied tissue from three patien ts with PCNs lymphoma. Immunosuppressive states and exposure to mutage ns were not clear in all patients. Results. Histopathologic examinatio n disclosed a diffuse type of malignant lymphoma in all patients. Immu nophenotypic studies revealed B cell phenotype in all patients, two of whom showed positive reaction for CD5. The PCR method revealed no inv olvement of EBV genome in tumors in any patients. The cytogenetic stud y showed clonal chromosome abnormalities in all patients, and abnormal ities of chromosome 1 (1q21), 6 (-6, 6q15 and 6q21), 7 (-7 and 7p15), and 14 (14q24 and 14q32) were prominent. The t(6;14)tq15;q32) observed in Patient 1 is the first case to be reported in human de novo lympho ma. Conclusions. These findings indicate that the causative role of EB V in PCNS lymphoma without immune defects is not clear. The cytogeneti c findings were similar to those observed in nodal B-cell lymphoma, su ggesting that the origin of PCNs lymphoma cells does not differ from n odal B cell lymphoma cells cytogenetically.