POLYMORPHOUS HIGH-GRADE B-CELL LYMPHOMA IS THE PREDOMINANT TYPE OF SPONTANEOUS PRIMARY CEREBRAL MALIGNANT-LYMPHOMAS - HISTOLOGICAL AND IMMUNOMORPHOLOGICAL EVALUATION OF COMPUTED TOMOGRAPHY-GUIDED STEREOTAXIC BRAIN BIOPSIES

In this retrospective study, a series of 54 patients (1982-1989) with sporadic primary cerebral malignant lymphomas is presented. All diagno ses were uniformly done on computed tomography-guided stereotactic bra in biopsies according to histological criteria and immunomorphological data. In this series, the tumors were predominantly (25 of 48; 52%) c lassified as polymorphous high-grade blastic B cell lymphomas. This ly mphoma type is therefore regarded as the most common type of sporadic primary cerebral non-Hodgkin's lymphoma. Severe regression (+ +/+ + +) , which may dramatically alter the morphological appearance of a brain lymphoma, was found in 24 of 28 (86%) of cases with glucocorticoid ad ministration prior to stereotactic brain biopsy.