Paraseller meningiomas: incidence of involvement of extracavernous structures as determined by magnetic resonance and computed tomography

Malignant trigeminal schwannoma extending into the anterior skull base

Malignant schwannomas are rare tumours that seldom grow in the head and neck and their occurrence is even rarer in patients not affected by neurofibromatosis. The authors report a 40 year old woman with a left trigeminal malignant schwannoma (arising from V2), involving the infratemporal fossa and subsequently extending into the maxillary, sphenoid and ethmoidal sinuses, the orbit, and the intracranial compartment. Given the complex location of this tumour, the patient initially underwent radiation treatment; however due to a poor response to this form of treatment as well as disease progression, surgical resection requiring a combined Neurosurgical, ENT and Plastic Surgery was recommended. The planned operation included sacrificing the internal carotid artery and cavernous sinus, ipsilateral orbit exenteration and reconstruction with a free flap from the latissimus dorsi muscle. In this report, we discuss the sporadic occurrence of these tumours, the histo-pathological features and the management strategy along with a review of the literature.

Cavernous sinus exenteration for invasive cranial base tumors

OBJECTIVE

Invasive tumors involving the cavernous sinus, such as recurrent benign meningiomas or sarcomas, raise therapeutic problems that may be resolved by cavernous sinus exenteration (CSE).

METHODS

Our series comprises 18 patients (9 women and 9 men ranging in age from 14 to 64 yr) who underwent CSE during the past 8 years. The tumors in these patients included 12 meningiomas, 3 chondrosarcomas, 1 rhabdomyosarcoma, 1 lipomyosarcoma, and 1 epidermoid carcinoma. Preoperative occlusion of the internal carotid artery was confirmed in 15 cases by a balloon occlusion test. Three patients had a negative balloon occlusion test, and their internal carotid arteries were preserved (n = 1) or revascularized (n = 2) through an external carotid artery-to-middle cerebral artery bypass.

RESULTS

CSE was performed as a primary treatment in 5 patients and after one to five recurrences in 13 patients. In all patients, CSE included the internal carotid artery and Cranial Nerves III, IV, and VI and one to three branches of Cranial Nerve V. Orbital exenteration was performed in eight patients, and partial hypophysectomy was performed in five patients. Ten patients had received radiotherapy before CSE, and five patients underwent irradiation after CSE. The operative mortality includes two patients. Cerebrospinal fluid leakage was the main complication in four patients, with three patients having meningitis. Follow-up ranged from 6 months to 5 years, with three deaths from new recurrences at 2, 3, and 4 years after CSE. As compared with their clinical courses before CSE, all patients except the two who died postoperatively benefited from CSE.

CONCLUSION

CSE has useful indications in invasive and rapidly growing tumors, including apparently benign meningiomas. A better understanding of the biological behavior of these tumors is necessary for appropriate selection of patients for CSE.

Invasion of the internal carotid artery by cavernous sinus meningiomas

BACKGROUND

Meningiomas are the most common tumor involving the cavernous sinus. Although these tumors have been known to invade adjacent structures such as bone, soft tissue, and brain, invasion of the internal carotid artery (ICA) by meningiomas has only been recognized recently. The authors evaluate the extent of carotid wall involvement in nine patients with cavernous sinus meningiomas encasing the ICA who underwent en bloc resection of the cavernous sinus.

METHODS

The en bloc tumor-ICA specimens were fixed in formalin, embedded in paraffin, and sectioned on a rotary microtome. Hematoxylin and eosin, EVG, and HVG stains were performed and evaluated by light microscopy.

RESULTS

There were four males and five females with a mean age of 47 years. Eight patients had not undergone previous surgery, whereas one patient had been operated on before. In this latter case, however, the cavernous sinus was not entered during the first operation. In all patients, stenosis of the ICA was confirmed by preoperative angiography and/or magnetic resonance imaging (MRI). In seven cases, the tumors were excised en bloc along with the stenotic ICA segment. A petrous-to-supraclinoid ICA bypass was performed in these seven patients. In two cases, the tumor was excised with the stenotic artery, but no bypass was performed. The final pathological diagnosis was meningothelial meningioma. In all cases tumor cells were found in the adventitia of the cavernous carotid with stenosis of the arterial lumen. Compression and/or obliteration of the vasa vasorum within the adventia was noted in all specimens. In four cases, the tumor was found to have invaded the external elastic lamina. In two instances the external elastic lamina was disrupted and the tumor focally extended into the media.

CONCLUSIONS

These findings suggest that in the case of cavernous sinus meningiomas with encasement and stenosis of the intracavernous ICA, invasion of the vessel wall has occurred. The effect of these findings on the management of cavernous sinus meningiomas and the involved ICA is discussed.