Cysts in malignant gliomas. Identification by computerized tomography.

The clinical course, computerized tomography (CT) scans, and postmortem reports for 265 patients treated for malignant brain tumors were reviewed. Forty-one patients underwent reoperation for tumor recurrence and one had needle aspiration as a diagnostic procedure; of these patients, seven (3% of 265 and 17% of 42) were diagnosed as harboring tumor cysts and 10 (25% of 41) as having necrotic tumor centers. The CT scans on the 17 patients harboring tumors with surgically confirmed cysts and necrotic centers were reviewed; criteria for distinguishing between cysts and central necrosis are suggested. The relative benefits of repeated aspiration and surgical therapy for these cystic lesions are discussed.