Abstract
The incidence of recurrence was examined in 174 patients with completely removed meningioma. The material consisted of 284 surgically treated cases with meningioma from January 1941 through March 1976. Following operations of grade III (Simpson), there appeared to have been 16.1 % of recurrence, 20.0% following operations of grade II and 18.8% following ones of grade I. The recurrent site of tumors was, convexity, falx, olfactory groove, parasagittal, tuberculum sellae and sphenoid ridge, in decreasing frequency.
Eight out of 17 malignant meningiomas (47%) and 1 out of 4 hemangiopericytoma type of angioblastic meningiomas recurred. Out of 149 tumors diagnosed as benign meningiomas in the original operations, 19 (12.7 %) recurred. The recurrence rate was 13.3% in meningocytic meningiomas and 9.5% in fibroblastic ones. Most recurrent meningiomas did not show morphological changes. However, 6 out of 19 recurrent meningiomas (31.6%) showed histologically malignant changes. All 6 tumors had been meningocytic in the original operations. All the histologically malignant meningiomas carried also malignant biological character.
Even after excluding those diagnosed as malignant in the original operations, the recurrence rates were 5.7% in grade III operations, 16.9% in grade II and 14.6% in grade I operations. The recurrent site of originally benign meningiomas was following in decreasing frequency; falx, olfactory groove, convexity, parasagittal and tuberculum sellae.
It was not established whether prophylactic radiation therapy was effective in preventing repeated recurrence in benign meningiomas.
