NON-HODGKIN LYMPHOMAS OF THE CENTRAL-NERVOUS-SYSTEM - CLINICOPATHOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY OF 147 CASES

We report on data gathered from five European centres regarding 147 pr imary non-Hodgkin Lymphomas (NHLs) of the Central Nervous System (CNS) in HIV-negative patients. The results lead us to make the following c onsiderations: i)there has been a significant and progressive increase in the frequency of observation of this pathology during the course o f the last two decades; ii) the pathology lacks specific characteristi c symptoms; iii) the radiological profile, as observed by CAT and/or M NR, most frequently corresponds to an isodense or slightly hyperdense lesion which has clear margins and is capable of assuming the contrast medium homogeneously; iv) the tumour most often has a single supraten torial localisation; v) high grade B-cell lymphomas account for 66 % o f the observations, low grade B-cell varieties being relatively rare a nd cases of T-cell derivation exceptional (6/147); vi) immunohistochem istry allows the differential diagnoses with respect to primitive or s econdary non-lymphoid tumours, and provides confirmation of the histog enetic assessment made on morphological grounds; vii) the course of th e disease is not significantly influenced by the histotype, the phenot ype, the number of lesions present or the chemotherapy regimen, but ra ther by the employment of combined surgery and radio- or radiochemothe rapy. This study represents the largest series of CNS NHLs so far repo rted, and as such, provides precise clinico-pathological indications w hich were only partially obtainable from the relatively small previous ly published series. Some concluding remarks are made as to the genesi s of CNS NHLs, along with some practical suggestions for reaching a be tter understanding of their complex biology.