Combined transmandibular-zygomatic approach and infratemporal craniotomy for intracranial skull base tumors.

Large intracranial skull base tumors remain surgically treacherous lesions. The preauricular transzygomatic infratemporal approach to this area has rapidly gained popularity. This article presents modifications to this approach which improved visualization and access to the infratemporal fossa. The procedure increases visualization, minimizes brain retraction, and results in improved resection and outcome. Reconstruction is rapid and there are minimal functional and cosmetic deficits.

Primary central nervous system lymphoma.

Primary central nervous system lymphomas constitute less than 2% of primary brain tumors. Although their cause is unknown, they are in some way related to immunosuppression. The typical patient is a middle-aged man who displays the syndrome of a subacute mass lesion. These tumors most commonly occur as a single, bulky mass in the hemispheric white matter or the deep gray matter, but multiple tumors occur in approximately a fourth of the patients. The findings on computed tomography are distinctive and nearly pathognomonic. The majority of these tumors are B-cell lymphomas with aggressive histologic changes. Surgical intervention should be reserved for tissue diagnosis because surgical removal does not seem to influence the outcome. Conventional therapy consists of whole-brain irradiation with or without chemotherapy. The prognosis for patients with such tumors is grim, the median duration of survival being less than 2 years with conventional therapy and the 5-year survival being less than 5%.

Imaging-based stereotaxic serial biopsies in untreated intracranial glial neoplasms.

Forty patients with previously untreated intracranial glial neoplasms underwent stereotaxic serial biopsies assisted by computerized tomography (CT) and magnetic resonance imaging (MRI). Tumor volumes defined by computer reconstruction of contrast enhancement and low-attenuation boundaries on CT and T1 and T2 prolongation on MRI revealed that tumor volumes defined by T2-weighted MRI scans were larger than those defined by low-attenuation or contrast enhancement on CT scans. Histological analysis of 195 biopsy specimens obtained from various locations within the volumes defined by CT and MRI revealed that: contrast enhancement most often corresponded to tumor tissue without intervening parenchyma; hypodensity corresponded to parenchyma infiltrated by isolated tumor cells or in some instances to tumor tissue in low-grade gliomas or to simple edema; and isolated tumor cell infiltration extended at least as far as T2 prolongation on magnetic resonance images. This information may be useful in planning surgical procedures and radiation therapy in patients with intracranial glial neoplasms.