✓ The management of 21 parasagittal meningiomas is described; three were located in the anterior third of the sinus, 14 in the middle third, and four in the posterior third. Of these, four meningiomas were attached only to the lateral wall, two invaded the external layer of only one sinus wall, two involved the lateral recess of the sinus, and seven invaded one or two sinus walls. The remaining six tumors invaded the three walls of the sinus, which was completely blocked. There were bilateral meningiomas in four cases. Complete excision of the meningioma with preservation of the venous flow in the sinus and its collateral veins was attempted in each case. In the first eight cases it was possible to preserve the patency of the sinus without graft. In six of the next seven cases the removal of the two invaded walls permitted preservation of the third healthy wall and entailed the repair of the two involved walls by a partial graft, either dural graft (three cases) or venous graft (three cases). In one of the last six cases, a total vein graft was performed after complete excision of the invaded sinus. Two cortical veins were sutured to a collateral branch of the autogenous vein graft. The surgical technique of the partial and the total vein graft is described and clinical results and angiographic controls are discussed.
Joel Bonnal and Jacques Brotchi
Joël Bonnal, André Thibaut, Jacques Brotchi, and Jacques Born
✓ The authors report a series of 34 meningiomas of the sphenoid ridge. Eight tumors were totally removed uneventfully: two from the middle sphenoid ridge and six from the pterion or Sylvian point. Five tumors were not operated on because of their extensions or the patient's age. Twenty-one tumors raised serious surgical problems, resulting in a classification into three groups: deep or clinoidal, invading beyond the sphenoid wings, and a combination of both. Histological study of the hyperostotic bone showed meningiomatous cells in the bone in 12 of 13 cases so examined.
Surgical limitations included invasion of the cavernous sinus (15 cases), of the dura mater of the sella turcica (seven cases), of the lateral part of the sphenoid body at the insertion point of the ala magna (seven cases), and of the common tendinous annulus of Zinn in the orbit (five cases), and basilar extracranial extension, particularly in the pterygomaxillary fossa (three cases). Following extensive removal, there were no early recurrences and three late recurrences (9 years and more). In 13 cases with a follow-up period of 1 to 8 years, there were no clinical recurrences. In only two cases was the meningioma totally removed. There were three postoperative deaths, two cases of hemiparesis with aphasia and epilepsy, one case with a frontal lobe syndrome, and nine with slight oculomotor, visual, or esthetic sequelae.
Isabelle Salmon, Olivier Dewitte, Jean-Lambert Pasteels, Jacqueline Flament-Durand, Jacques Brotchi, Pierre Vereerstraeten, and Robert Kiss
✓ High-grade astrocytic tumors constitute the most serious as well as the most common group of primary brain tumors. Although several prognostic factors have been proposed, little is known about the prognostic value of deoxyribonucleic acid (DNA) ploidy in adult astrocytic tumors. In a series of 146 adult patients, aged 16 to 82 years, the individual prognostic values of six variables were studied, namely: tumor histopathological grade, treatment, patient age, extent of tumor, ploidy level, and DNA histogram type. Cox's proportional hazard model was then applied to the data to ascertain which factors might independently determine patient survival. Univariate analyses revealed that histopathological grade, age, and DNA histogram type were very powerful prognostic factors. The statistical significance of the influence of adjuvant radiotherapy and chemotherapy was at a borderline level, and the two remaining variables (tumor extent and ploidy level) had no prognostic relevance. Multivariate analyses showed that age, histopathological grade, and DNA histogram type were independent, statistically significant prognostic factors.
A prognostic score was calculated from Cox's polynomial function in which those factors were introduced. The best score corresponded to a patient aged 16 years with a hypertriploid low-grade astrocytoma, while the worst score corresponded to a patient aged 82 years with a diploid high-grade astrocytoma. The worst score:best score ratio revealed a risk 71 times higher for a bad prognosis. It is concluded that patient age, histopathological grade, and DNA histogram type are very powerful prognostic factors for adult astrocytic tumors. A prognostic score including those factors could be used to characterize astrocytic tumor aggressiveness presurgically on fine-needle aspirates, and to monitor the patient's postsurgical evolution to define the appropriate therapy.
Marc Levivier, Serge Goldman, Benoît Pirotte, Jean-Marie Brucher, Danielle Balériaux, André Luxen, Jerzy Hildebrand, and Jacques Brotchi
✓ The aim of the present study was to determine whether routine integration of positron emission tomography (PET) with 18F-labeled fluorodeoxyglucose (FDG) in the planning of stereotactic brain biopsy increases the technique's diagnostic yield. Forty-three patients underwent combined FDG-PET— and computerized tomography (CT)-guided stereotactic biopsy of intracranial lesions according to a previously described technique. In 36 patients, an area of abnormal FDG uptake was used to guide at least one stereotactic biopsy trajectory. A total of 90 stereotactic trajectories were performed; among them, 55 were based on FDG-PET—defined targets and 35 were based on CT-defined targets. Histological diagnosis was obtained in all patients, but six of the 90 trajectories were nondiagnostic; all six were based on targets defined by CT only. Differences between the diagnostic yield of trajectories based on FDG-PET—defined targets and those based on CT-defined targets were statistically significant in patients with contrast-enhanced lesions, but not in patients with nonenhancing lesions. These results support the view the FDG-PET may contribute to the successful management of brain tumor patients requiring stereotactic biopsy. Because no significant increase in discomfort or morbidity related to the technique was found, it is suggested that the development of similar techniques integrating PET data in the planning of stereotactic biopsy should be considered by centers performing stereotactic surgery and having access to PET technology.
Christine Decaestecker, Isabelle Salmon, Olivier Dewitte, Isabelle Camby, Philippe Van Ham, Jean-Lambert Pasteels, Jacques Brotchi, and Robert Kiss
✓ The authors investigated whether cytometry-related variables generated by means of computer-assisted microscopic analysis of Feulgen-stained nuclei can contribute significant information toward the characterization of low-grade astrocytic tumor aggressiveness. This investigation was conducted using the nearest-neighbor rule (a traditional classification method used in pattern recognition) to analyze a series of 250 supratentorial astrocytic tumors from adult patients. This series included 39 low-grade astrocytomas and 211 high-grade astrocytic tumors (including 47 anaplastic astrocytomas and 164 glioblastomas multiforme [GBMs]). The results show that the 3-nearest-neighbors rule enabled a subgroup of “atypical” astrocytomas to be distinguished from the “typical” tumors. The atypical astrocytoma species exhibited a DNA content (DNA ploidy level) and morphonuclear characteristics that were statistically more similar to the characteristics of GBMs than to those exhibited by the typical astrocytomas. An analysis of survival data revealed that patients with atypical astrocytomas survived for a significantly shorter period (p < 0.001) than patients with typical lesions of this kind. In fact, patients with atypical astrocytomas had a survival period similar to that of patients with anaplastic astrocytomas, whereas patients with typical astrocytomas had a survival period significantly longer (p < 0.0001) than those associated with anaplastic astrocytomas and GBMs.
Case report and review of the literature
Benoît Pirotte, Boris Krischek, Marc Levivier, Serge Bolyn, Jean-Marie Brucher, and Jacques Brotchi
✓ Angiolipomas (ALs) are hamartomas composed of abnormally differentiated vessels and mature adipose tissue. Although they are most commonly found in peripheral tissues, ALs sometimes grow in the spinal epidural space. Intracranial ALs (ICALs) are rare: only seven cases have been reported in the literature. The authors describe the case of a 70-year-old woman who presented with ocular symptoms from a clinically and radiologically progressing parasellar ICAL. The radiological as well as the microsurgical findings are illustrated and compared with the seven previously published cases. The most frequent location of ALs is the skull base, especially the parasellar region. Other ICALs were diagnosed as components of cerebral arteriovenous malformations and were not symptomatic by themselves. Neuroradiological studies of ICALs usually demonstrate the characteristics of both adipose and vascular tissues. However, a review of the literature shows that the diagnosis had not been suspected preoperatively in any of the cases. Operative descriptions emphasize that most neurosurgeons were caught off guard by the profuse bleeding and the unusual relationship of this unexpected lesion to the cavernous sinus, so that removal was rarely complete. The authors conclude that preoperative diagnosis of ICALs is achievable based on magnetic resonance analysis, which should help optimize the microsurgical management of these lesions.
Jacques Brotchi and Georges Fischer
Ependymomas are the most frequent spinal cord tumors in adult patients. Although magnetic resonance imaging can be a highly accurate diagnostic tool, it does not always provide accurate differentiation between ependymomas and astrocytomas. This is why the authors recommend surgical resection and histological evaluation in all intraspinal cord tumors. It cannot be said that a tumor is unresectable without first attempting to remove it. Complete removal should be accomplished whenever possible, and patients should undergo operation before they become neurologically impaired. Quality of life depends on preoperative neurological status. Postoperative radiotherapy should be avoided in all low-grade ependymomas even after partial removal. Radiotherapy may be used to treat anaplastic ependymomas, which are quite rare in the spinal cord. Patients with low-grade ependymomas must be followed for years and undergo reoperation if necessary. In our experience treating 93 spinal cord ependymomas, complete removal was achieved in 86 patients and only one patient underwent reoperation 18 years later for tumor recurrence. The gold standard in treatment protocol is gross-total resection without adjunctive radiation therapy. Good long-term outcomes have been achieved by using this strategy.
Nicolas Massager, Philippe David, Serge Goldman, Benoît Pirotte, David Wikler, Isabelle Salmon, Nathalie Nagy, Jacques Brotchi, and Marc Levivier
In the management of brainstem lesions, the place of stereotactic biopsy sampling remains debatable. The authors compared the results of magnetic resonance (MR) imaging, positron emission tomography (PET), and histological findings obtained in 30 patients who underwent an MR image– and PET-guided stereotactic biopsy procedure for a brainstem mass lesion.
Between July 1991 and December 1998, 30 patients harboring a brainstem mass lesion underwent a stereotactic procedure in which combined MR imaging and PET guidance was used. Positron emission tomography scanning was performed using [18F]-fluorodeoxyglucose in 16 patients, methionine in two patients, and with both tracers in 12 patients. Definite diagnosis was established on histological examination of the biopsy samples. Interpretation of MR imaging findings only or PET findings only were in agreement with the histological diagnosis in 63% and 73% of cases, respectively. Magnetic resonance imaging and PET findings were concordant in 19 of the 30 cases; in those cases, imaging data correlated with histological findings in 79%. In seven patients who underwent one PET-defined and one MR imaging–defined trajectory, at histological examination the PET-guided samples were more representative of the tumor's nature and grade than the MR imaging–guided samples in four cases (57%). In 18 patients PET scanning was used to define a biopsy target and provided a diagnostic yield in 100% of the cases.
Although the use of combined PET and MR imaging improves radiological interpretation of a mass lesion in the brainstem, it does not accurately replace histological diagnosis that is provided by a stereotactically obtained biopsy sample. Combined information provided by MR imaging and PET in stereotactic conditions improves the accuracy of targeting and the diagnostic yield of the stereotactically biopsy sample; an MR imaging– and PET-guided stereotactic biopsy procedure is a safe and efficient modality for the management of mass lesions of the brainstem.