A clinicopathological study of 21 cases of primary central nervous system lymphoma

: A clinico-pathological study was carried out in 21 cases of primary central nervous system-non-Hodgkin's lymphoma (CNS-NHL). Their clinical profiles (age, prognosis, modalities of treatment) and findings of radio-imaging were analyzed. All specimens from surgery and/or autopsy were histologically classified according to the working formulation (WF) classification of the National Cancer Institute. Ontogeny of lymphoma cells was determined by immunohistochemical study in all cases and some cases were subjected to light (kappa, lambda) and heavy chain (IgG, IgA, IgM) analysis as well. Among 21 cases, 12 cases were located in the cerebral hemisphere, 7 in the thalamus-basal ganglia and 4 in the cerebellum. Radio-imaging study showed that 18 cases (86%) revealed isodensity mass lesions on plain CT, which were homogeneously enhanced by contrast medium. The pathological study showed that all cases were derived from B-cells. Five were classified as immunoblastic type (IBL), 9 as diffuse large type (DL), and the others were classified according to WF. 17 of 21 cases (81%) were sensitive to radiotherapy, and 15 of 19 cases (79%) responded to corticosteroid. A prognostic study revealed that patients with IBL had less hope than those with DL. From this result, it seems that WF classification is better than LSG classification for obtaining a prognosis in malignant lymphoma patients. The frequency of primary CNS-NHL has been increasing for the past several decades and will surpass that of any other brain tumors in the near future because of the explosive expansion of AIDS patients. Therefore, not only clinicopathological analysis but also biological study for CNS-NHL might be important.