Clinical analysis of 27 patients with primary central nervous system lymphoma--Out of 4397 patients with intracranial neoplasms treated in the Department of Neurosurgery Medical Academy in Poznań between years 1956-1990, 27 patients i.e. 0.6% had primary central nervous system lymphoma. The patients age ranged from 15 to 63 years. In most patients the tumour was located in the temporo-parietal region. All patients were treated surgically, and then some received radio and/or chemotherapy. In spite of combined therapy the results of treatment are unsatisfactory, the median survival time is between 2 and 4 months.