Incidental stereotactic diagnosis of cerebral insults.

Among the patients (6854 patients 1990-1999) who underwent computer-assisted stereotactic biopsy most were referred with the presumptive diagnosis of a brain mass lesion. Forty-three cases (0.63%) were found in which the final histopathological diagnosis excluded a neoplastic, infectious or inflammatory lesion but disclosed a cerebral insult. Histologically these could be subdivided into ischemic insults in 38 cases (88%) and hemorrhagic insults in five cases (12%). On the basis of clinical and radiological findings in this group, 35 patients (81%) were sent to our department because of suspected neoplasmatic lesions, two patients (5%) because of multiple sclerosis, two patients (5%) because of inflammatory disease and one patient (2%) because of a suspected infectious parasitic disease. All patients underwent initial CT examinations which showed hypodense lesions of the brain in 38 patients (88%) and hyperdense lesions in five cases (12%). Constant enhancement on CT scans of the mass lesion was found in 12 patients (28%) only. Fourteen lesions (33%) were located in the right hemisphere, five lesions (12%) in the left hemisphere, nine lesions (21%) in the basal ganglia, four lesions (9%) in the midbrain, two lesions (4.5%) in the corpus callosum and one lesion (2%) in a thalamus. Multiple lesions were present in eight cases (19%). The most common initial neurological symptoms upon clinical presentation were hemiparesis (18 patients, 42%), epilepsy (eight patients, 18%), a change in mental status (six patients, 14%). There was no mortality and no operative morbidity associated with the stereotactic biopsy in this group of patients. The most common neurological disorder, cerebrovascular insult, rarely poses diagnostic problems. If there are doubts a serial stereotactic biopsy can safely clarify the situation.