Invasion of the internal carotid artery by cavernous sinus meningiomas

BACKGROUND Meningiomas are the most common tumor involving the cavernous sinus. Althou gh these tumors have been known to invade adjacent structures such as bone, soft tissue, and brain, invasion of the internal carotid artery (ICA) by m eningiomas has only been recognized recently. The authors evaluate the exte nt of carotid wall involvement in nine patients with cavernous sinus mening iomas encasing the ICA who underwent en bloc resection of the cavernous sin us. METHODS The en bloc tumor-ICA specimens were fixed in formalin, embedded in paraffi n, 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 p atients had not undergone previous surgery, whereas one patient had been op erated on before. In this latter case, however, the cavernous sinus was not entered during the first operation. In all patients, stenosis of the ICA w as confirmed by preoperative angiography and/or magnetic resonance imaging (MRI). In seven cases, the tumors were excised en bloc along with the steno tic ICA segment. A petrous-to-supraclinoid ICA bypass was performed in thes e seven patients. In two cases, the tumor was excised with the stenotic art ery, but no bypass was performed. The final pathological diagnosis was meni ngothelial meningioma. In all cases tumor cells were found in the adventiti a of the cavernous carotid with stenosis of the arterial lumen. Compression and/or obliteration of the vasa vasorum within the adventia was noted in a ll specimens. In four cases, the tumor was found to have invaded the extern al elastic lamina, In two instances the external elastic lamina was disrupt ed 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 cavern ous sinus meningiomas and the involved ICA is discussed. (C) 1999 by Elsevi er Science Inc.