Primary malignant lymphoma of the central nervous system.

The occurrence of primary malignant lymphomas of the central nervous system in a population of approximately 1 million people has been analyzed retrospectively. Over a 12-year period, about 1000 tumors of the central nervous system were registered. Among these, 22 were primary malignant lymphomas; incidence, 1.83 per million per year. Thirteen of these tumors were of high-grade malignancy and nine were of low-grade malignancy (Kiel classification of non-Hodgkin lymphomas). The majority of the tumors were B-cell lymphomas, and there were no Hodgkin lymphomas. Neither spinal nor meningeal lymphomas occurred. Nine patients were treated only surgically, whereas 11 received postoperative irradiation or chemotherapy, or both. Of the latter patients, six are alive and well at the time of writing. The importance of making a correct diagnosis preoperatively is stressed, inasmuch as radical operation is unfavorable for these patients. A better prognosis is obtained with combinations of irradiation and chemotherapy.