Juxtasellar hyperostosis of non-meningiomatous origin

Seven patients are described who had juxtasellar hyperostosis with visual disturbance secondary to non-meningiomatous lesions. Two had chromophobe adenomas, one craniopharyngioma, one carcinoma of the sphenoid sinus, one a thrombosed aneurysm of the intracavernous portion of the internal carotid artery, one epidermoidoma of the orbit, and one chondroblastoma of the anterior clinoid process. The diagnosis of meningioma was entertained initially on the basis of hyperostosis plus visual impairment. Careful evaluation of hyperostosis is essential for correct diagnosis of meningioma, according to our experience. Suprasellar meningiomas almost invariably produce irregular hyperostosis of the planum sphenoidale, often associated with serration and blistering. Sphenoid meningioma, when it is sclerotic, always shows thickening or expansion of the sphenoid wings. Therefore, in the absence of typical meningiomatous hyperostosis, one can readily differentiate non-meningiomatous hyperostosis from true meningioma.

The diagnostic value of hyperostosis in midline subfrontal meningioma

Roentgenologic analysis of 66 patients with proved midline subfrontal meningioma indicates a very high incidence of hyperostosis. A total of 63 patients (95%) showed varying degrees of hyperostosis involving the cribiform plate, planum sphenoidale, or tuberculum sellae (including the chiasmatic sulcus). The planum sphenoidale is the most common site of hyperostosis (59%). In 19 cases (29%), the region of hyperostosis did not correspond to the site of tumor attachment. Mild or localized hyperostosis may be apparent only on tomograms. Small "blistering" and "saw-tooth-like" osteoma formation are reliable early signs of midline subfrontal meningioma; conversely, midline subfrontal meningioma can be virtually ruled out if hyperostosis is absent.

Angiographic findings in recurrent meningioma

Of 147 patients who underwent radical surgery for intracranial meningioma, 25 (17%) had symptomatic recurrence requiring further surgery. Correlation between histological and angiographic findings of recurrent meningioma was poor. Following extirpation of feeding meningeal vessels in convexity meningiomas, the principal blood supply was usually from the anterior, middle, and/or posterior cerebral arteries. The angiographic appearance was that of a "tree-root" or "sunburst" pattern, indicating neoplastic invasion of the pia mater and/or underlying brain tissue. Polytomography, selective cerebral angiography, and radionuclide imaging of the brain are often necessary to detect early recurrent meningiomas. Computed tomography appears to be an innocuous and accurate method of diagnosing recurrent tumor, especially when the bone is not involved.

Ischemic chiasmal syndrome

Twenty-two patients with ischemic chiasmal syndrome (ICS) have been examined by means of magnification angiography and polytomographic encephalography. The causes of ICS may be divided into 5 categories: (1) mechanical compression of the chiasm by ectatic redundant anterior cerebral arteries, (2) atherosclerotic vascular occlusions, (3) optochiasmal arachnoidal fibrosis, (4) various forms of arteritis especially giant cell (cranial) arteritis, and (5) post-partum pituitary necrosis associated with ICS. The most common cause of ICS appears to be optochiasmal arachnoiditis which occasionally developed some time after a craniotomy and radiation therapy for pituitary or other juxta-sellar tumors; similar fibrotic change may develop following steroid treatment of granulomatous lesions.