Primary intracranial malignant lymphomas with particular reference to their pathogenesis.

During the past 6 years we have experienced a total of 6 cases of malignant lymphomas, which originated primarily in the central nervous system. The most reliable diagnostic criteria will be a "perivascular cuffing" by silver impregnation with further spreading of tumor cells to the periphery, a "starry-sky" appearance consisting of numerous histiocytes with foamy cytoplasm intermingled with tumor cells, and cytological features of the imprint preparation. Since there is a close histologic similarity to extracerebral malignant lymphomas, we would like to propose that these tumors should be regarded as primary malignant lymphomas of the central nervous system instead of mere reticulum cell sarcoma-microglioma, and also would like to regard the brain to be not an exceptional site other than visceral lymphomas for occurrences of malignant lymphomas. For the pathogenesis of primary intracranial malignant lymphomas, the hypothesis, proposed by FEIGIN, of the possible existence of multipotential stem cells in the brain was discussed.