Benign nonmeningeal tumors of the cavernous sinus.

OBJECTIVE: Resection of benign cavernous sinus tumors with minimum morbidity and mortality is increasingly more common. Although meningiomas have dominated most discussions, numerous nonmeningeal tumors also deserve attention because they are generally more amenable to radical surgical resection. METHODS: We reviewed the records of 40 patients (19 female and 21 male patients) who were treated surgically during a 15-year period for benign, nonmeningeal tumors of the cavernous sinus. Invasive pituitary adenomas (14 cases) and trigeminal schwannomas (13 cases) comprised the majority of tumors; the remaining tumor types were hemangioma, neurofibroma, juvenile angiofibroma, dermoid tumor, giant cell tumor, chondromyxofibroma, and chondroma. Patient age ranged from 7 to 65 years (mean, 37 yr). RESULTS: All patients underwent surgery, the intent being total resection. Total resection was achieved in 33 (82.5%) of the 40 patients. Follow-up was achieved via a combination of direct patient visit or phone interview or via the referring physician. Eight patients had undergone previous surgery elsewhere, which correlated closely with complications and neurophthalmological outcomes but did not affect resectability. Postoperatively, 89.7% of the patients had either stable or improved extraocular muscle function compared with their preoperative statuses. Forty percent of the patients experienced improvement of their preoperative extraocular muscle deficits. Complications included cerebrospinal fluid leak (three cases), postoperative hemorrhage (one case), fat embolism (one case), perforator distribution infarct (one case), hydrocephalus requiring ventriculoperitoneal shunting (two cases), transient hemiparesis (one case), and diabetes insipidus (one case). CONCLUSION: We conclude that benign nonmeningeal tumors of the cavernous sinus can be safely and radically removed and result in good long-term neuro-ophthalmological function and low morbidity and mortality. Furthermore, when compared with our previously reported results for cavernous sinus meningiomas, benign nonmeningeal tumors of the cavernous sinus carry a better chance of total removal, a lower incidence of postoperative ocular dysfunction, and a higher rate of recovery of preoperative cranial nerve deficits.

Abscess formation within a parasagittal meningioma. Case report.

The authors present the case of a 78-year-old woman who developed right lower-extremity paralysis after a focal seizure. Neuroradiological studies revealed a small parasagittal meningioma, which at the time of resection was found to contain a bacterial intratumoral abscess secondary to Proteus mirabilis. This is only the second reported case of intratumoral abscess formation in a meningioma and the first such occurrence to be reported in an otherwise healthy, immunocompetent individual.

Petrous apex cholesterol granulomas: evolution and management.

Petrous apex cholesterol granulomas result from obstruction of the normal aeration of the petrous air cells and have traditionally been treated by drainage and stent placement via a transtemporal approach. The immediate results were quite satisfying, but recurrence rates as high as 60% have been reported in some series. The authors present their experience treating 14 patients with petrous apex cholesterol granulomas. An extended middle fossa approach and a petrosal approach were used for eight and two patients, respectively. All underwent complete removal of the granuloma and cyst wall followed by obliteration of the cavity with a pedicled strip of temporalis muscle. No recurrences were seen at a mean follow-up period of 3.8 years. Four patients who did not undergo surgery are being followed clinically and with serial magnetic resonance images. Additionally, the clinical and radiographic findings in this series give new insights into the origin and continued growth of these lesions and confirm what had been described previously only in experimental models. It is concluded that petrous apex cholesterol granulomas feature a continuum of both clinical and radiographic findings and radical removal via an extended middle fossa approach is advocated.

Loss of heterozygosity in the retinoblastoma tumor suppressor gene in skull base chordomas and chondrosarcomas.

BACKGROUND: The retinoblastoma (Rb) gene is a well characterized tumor suppressor gene in which loss of heterozygosity has been implicated in a number of malignancies including osteosarcoma and breast carcinoma. Chordomas and chondrosarcomas are rare skull base neoplasms with a propensity for local recurrences, resistance to conventional radiotherapy, and a 5%-30% incidence of metastases. Except for the so called "chondroid chordoma," histologic features do not correlate with the clinical behavior or growth patterns of these tumors. No study to date has investigated what role tumor suppressor genes or oncogenes play in the development and continued growth of these rare neoplasms. METHODS: In order to evaluate the role of the retinoblastoma tumor suppressor gene in chordomas and chondrosarcomas we screened seven chordomas and two chondrosarcomas located at the skull base for loss of heterozygosity (LOH) of the Rb gene. Genomic DNA was extracted from tumor specimens as well as matched control tissue and utilizing a polymerase chain reaction technique, intron 17 and 20 were amplified from each specimen. The intron 17 product was then digested with the restriction endonuclease X ba1 followed by electrophoresis on a 1% agrose gel. The intron 20 amplified products were electrophoresed on a nondenaturing 6% polyacrylamide gel. RESULTS: We demonstrated LOH at intron 17 of the retinoblastoma gene in 2/7 chordomas and in 0/2 chondrosarcomas. The two chordomas possessing LOH were particularly aggressive tumors demonstrating extensive involvement of the skull base and rapid recurrences following radical resections. CONCLUSIONS: Alterations of the Rb gene may play a role in the growth of skull base chordomas with LOH of the Rb gene serving as a marker for more aggressive tumors. This report represents the first study evaluating the Rb gene in chordomas or chondrosarcomas and is the first report of allelic loss of the Rb gene in skull base chordomas.

Resection and replacement of the superior sagittal sinus for treatment of a parasagittal meningioma: technical case report.

We report a case of the complete resection of a parasagittal meningioma, including an 8-cm length of the superior sagittal sinus and adjacent dura. Flow through the sagittal sinus was reestablished through an interposed saphenous vein graft. Intraoperative angiography confirmed immediate patency of the graft, as did delayed angiography performed at 8 days. Follow-up magnetic resonance angiography 9 months after surgery demonstrated continued patency of the graft. Sagittal sinus replacement with a vein graft can be safely performed during Simpson Grade I resection of parasagittal meningiomas.

Hearing preservation in vestibular schwannoma surgery: what factors influence outcome?

The goals in the management of patients with vestibular schwannomas have changed drastically over the past few decades, with preservation of useful hearing representing the newest challenge. The true incidence of preserved useful hearing, however, has become clouded by a lack of uniformity in reporting results. The authors have analyzed 56 consecutive cases, in which directed attempts were made to preserve hearing on the involved side, to understand what factors play a major role in postoperative hearing preservation. Of the 56 cases reviewed, there were 46 patients who had "good" preoperative hearing (pure tone average < 50 dB; speech discrimination score > 50%). We found that, in this group of patients, if the tumor was less than 2 cm in diameter from pons to petrous, there was a 52% (16 of 31 patients) chance of preserving good hearing and if the tumor was 1 cm or less, the chances increased to 83%. Factors such as preoperative hearing status, tumor size and location, tumor consistency, and preoperative and intraoperative brainstem auditory evoked potentials are discussed in detail as they relate to postoperative outcome.

Symptomatic cavernous malformations affecting the spine and spinal cord.

Ten cases of symptomatic cavernous malformations affecting the spine and spinal cord were retrospectively reviewed. The cases display a spectrum of pathological findings involving the vertebral body, vertebral body with epidural extension, epidural space without bony involvement, intradural extramedullary space, and intramedullary lesions. Lesions at all locations are identical histologically, electron microscopically, and immunohistochemically. This perspective, in which cavernous malformations are envisioned as a single entity arising at numerous locations, runs contrary to the view found in the neurosurgical literature. In most discussions of cavernous malformations, vertebral body lesions are depicted as separate entities from intradural lesions. Cavernous malformations, also called cavernous hemangiomas, are developmental vascular hamartomas that, by definition, do not grow by mitotic activity. Yet, the expansion of these lesions is well documented both in the literature and among our cases. The therapeutic modalities used in our series included observation, embolization, radiation, and surgical resection alone or in combination. All modalities are effective but must be tailored to the specific needs and condition of the patient. The embryology, methods of treatment, and proposed mechanisms of growth, plus similarities and differences between cavernous malformations at each location, are reviewed. Analogies between spinal and intracranial lesions are presented. On the basis of this series and a review of the literature, we conclude that cavernous malformations represent a single entity regardless of location. Segregation based on location, as is prevalent throughout the neurosurgical literature, hinders an overall understanding of these lesions. Cavernous malformations are more appropriately viewed as a single pathological entity arising in a multitude of locations. The difficulties encountered when managing cavernous malformations at various locations are unique to the location and not the lesion.

Tension pneumocephalus associated with rupture of a middle fossa encephalocele. Case report.

Acquired nontraumatic (spontaneous) encephaloceles of the middle fossa are not common. Rupture of an encephalocele frequently leads to a cerebrospinal fluid fistula. Tension pneumocephalus consequent to rupture of an encephalocele has not been previously reported, but conceivably occurs by means of a ball-valve mechanism in the ensuing fistulous tract. An unusual case is presented of an elderly man who suffered acute life-threatening neurological symptoms from a tension pneumocephalus that likely developed from rupture of an acquired nontraumatic encephalocele of the left middle fossa. The symptoms correlated with the location of the intracranial abnormalities. The literature is reviewed and the pathophysiology of the lesion is discussed.

Posterior fossa arachnoid cyst presenting with an isolated twelfth nerve paresis. Case report and review of the literature.

An unusual case of a posterior fossa arachnoid cyst containing atypical fluid is described in a patient presenting with an isolated ipsilateral twelfth nerve paresis. Despite the chronicity of symptoms, surgical decompression resulted in a satisfactory functional recovery.