Irradiated meningiomas: a clinical evaluation.

Eighteen cases of intracranial meningioma that received preoperative or postoperative irradiation with 60Cobalt or Linac have been reviewed. Eight patients received preoperative irradiation because their tumours were very large, hypervascular, and surgically not readily accessible. Two angioblastic meningiomas of the haemangiopericytoma type responded well to irradiation and were easily extirpated. One of these developed a local recurrence and metastases to the lungs and liver nine years after surgery. The recurrent intracranial tumour and nodules in the lungs responded well to irradiation. The other six cases of meningiomas of meningothelial, transitional, or haemangioblastoma types, did not improve clinically or radiologically after irradiation. Ten cases received postoperative irradiation because their tumours were only partially removed or were histologically malignant. In all cases irradiation was most effective for recurrent tumours of the haemangiopericytoma type. This study indicates that irradiation is useful in tumours of the haemangiopericytoma type as an adjunct to surgery or for palliation in advanced stages. Irradiation may been effective in supressing recurrences in two cases of other types of meningioma, although the number of cases is too small to allow any definite conclusion.