Patterns of proliferation in cerebral lymphoreticular tumours.

A study of eighteen cases of primary lymphoreticular tumours in the brain is described. In four of these there were extraneural lesions and in one macroglobulinaema. The use of whole brain sections embedded in celloidin, and of metallic impregnation methods, revealed certain constant patterns of proliferation. The tumours were diffuse and multicentric; the leptomeninges and perivascular spaces especially in the subependymal regions were frequently involved. Mature microglia were active both in infiltrated and in apparently tumour-free regions.