Nucleolar organizing regions in primary intracranial malignant lymphomas

Twenty-two non-immunocompromised patients with primary intracranialmalignant lymphomas were examined on surgical material by using anargyrophilic method for the demonstration of nucleolar organizer regions asAg-NORs. The histopathological classifications of 22 patients included 3small lymphocytic, 7 small cleaved, 9 large cell, 1 mixed large and small,and 2 small non-cleaved type. The numbers of Ag-NOR of malignant lymphomapatients varied from 1.36 to 5.02 (mean 3.46 ± 0.25). The mean Ag-NORnumbers in the histopathological subtypes were small lymphocytic 1.63, smallcleaved 3.18, large 4.21, mixed large and small 3.47, and small non-cleaved3.78. The number of Ag-NORs in small lymphocytic type was significantly lessthan small cleaved or large cell type (p < 0.05). The small cleaved typealso had a smaller Ag-NOR number than the large cell type (p < 0.05).Except for two patients who had postoperative deterioration, 20 patientsreceived postoperative irradiation ranging from 36 to 54 Gy (median, 46 Gy).Sixteen patients had complete response to radiotherapy, and 4 had goodpartial response. Ten patients had tumor recurrence within the remissionperiod of 3 months to 7 years and 10 months (median 4.8 months). Threepatients with intracranial relapse at a remote site had a significantlylonger remission period (mean 57.3 months) than 7 with local relapse (mean6.29 months), p < 0.05. The mean Ag–NOR number of the short andlong remission period were 3.13 ± 0.34 and 3.81 ± 0.80,respectively. No significant difference was found between these two groups.The survival period was 3.2 months to 12 years (median 20 months). TheAg-NOR numbers of survival period less than or more than 20 months were 3.62± 0.40 and 3.27 ± 0.37, respectively. The Ag-NOR numbers didnot correlate with either the remission or the survival period. Theseresults indicate that Ag-NOR numbers may correlate with the histopathologictypes, but not with the prognosis of primary intracranial malignantlymphomas.