Teaching Case

A 27-year-old woman with headache, nausea, vomiting, and blurred vision, ptosis, ophthalmoplegia on the right side .

A 27-year-old woman was admitted with headache, nausea, vomiting and blurred vision on the right side. Neurological examination showed ptosis with an ophthalmoplegia of the right eye. An MRI study of the sellar-parasellar region was performed on sagittal, axial, coronal planes with SE T1, FSE T2 and post-gadolinium SE T1 sequences on a 1.5 T MR scanner. MRI study of the patient revealed an extraaxial mass arising from the lateral wall of right cavernous sinus, and extending to superior orbital fissure, orbital apex, pterygopalatine fossa; it was isointense to gray matter in all sequences with diffuse contrast enhancement. The mass was resected surgically.

Meningiomas are the most common tumors arising from the lateral wall of the cavernous sinus, and they are the most common nonglial primary brain tumors. They are basically adult tumors with peak incidence in between the ages of 40-60. Meningiomas are more common in females compared to males (2-4/ 1). They are derived from meningothelial cells concentrated in arachnoid villi which penetrate dura. Meningiomas can appear as focal lobulated masses (globose meningioma) or flat en plaque lesions. They are usually sharply circumscribed lesions with a well-delineated tumor-brain interface. Classical description divides meningiomas into four classes as meningotheliomatous (syncytial) meningioma, fibrous meningioma, transitional meningioma, angioblastic meningioma. World Health Organization divides meningiomas into three basic categories: meningioma (typical benign meningioma), atypical meningioma, anaplastic (malignant) meningioma. Common imaging features for meningiomas can be listed as hyperostosis of the neighboring osseous structures due to reactive changes to slowly growing and somewhat lower grade meningiomas , erosion of the neighboring bone due to mass effect of somewhat higher grade tumors, enlarged vascular channels ( especially along the traces of meningeal arteries, most prominent is middle meningeal artery), tumor calcifications on plain radiography; hyperdense appearance, calcifications, uniform contrast enhancement on computed tomography; dual vascular supply (dural to center, pial to periphery), sunburst appearance of enlarged dural feeders in tumor due to the presence of vessels radiating outward from the central vascular pedicle, prolonged vascular stain on angiography; typically isointense signal change with gray matter, strong contrast enhancement, cerebrovascular fluid-vascular cleft demarcating the brain-tumor interface and confirming its extraaxial location, dural tail sign on MRI. Dural tail sign is present in 60 % of the meningiomas, but the exact nature of the dural tail is controversial. Some investigators report tumor cells infiltrating the thickened dura, and some others report that the abnormally enhancing dura surrounding most of the meningiomas represents reactive change and does not necessarily indicate neoplastic involvement. Although dural tail sign is highly suggestive for meningiomas it is not specific, because some other lesions such as schwannoma, glioblastoma multiforme, metastases may also be occasionally associated with a dural tail. Five to ten % of the intracranial meningiomas have a parasellar location, mostly around the cavernous sinuses. They may invade adjacent structures such as bone, soft tissue, brain, and internal carotid artery. Cavernous sinus meningiomas may cause multiple cranial nerve palsies by invading or compressing cavernous sinus due to their close relationship to cranial nerves II to VI, and pituitary findings such as pituitary insufficiency due to invasion of the pituitary gland or compression of the gland or of the stalk if they are large enough. Schwannomas, metastases, direct invasion or perineural spread of head and neck malignancies, and cavernous sinus invasion by pituitary adenomas, lymphomas, granulomatous inflammations can mimic meningiomas at this area.