Name : Morteza
Family : Sanei Taheri
Affiliation :Radiology Department,Shohada Tajrish Hospital,SBMU
Academic Degree : Associate professor of Radiology
Resident : Razmin Aslani
Gender : Female
Age : 54
A 54 y/o woman with quadriparesia and headache
axial brain CT scan without contrast shows a mass in left side of magnum foramen with mass effect on medulla and oblitration of adjacent csf space axial, sagittal, coronal brain MRI with and without Gd show an enhancing mass at base of skull extent from anterior fossa (sphenoid) through sella, bilateral parasella, clivus, magnum foramen and upper cervical spine with encacement of arteries (ICA and MCA)
meningioma metastasis lymphoma schwannoma
Discussion (Related Text)
Meningiomas are solid,sometimes spherical, sometimes lobulated, and sometimes flat and broad-based tumors Most commonly, they project inward from the dura, indenting and compressing the underlying brain, causing neurologic symptoms and signs through compression of the adjacent cortex. Common sites of origin are in the frontal and parietal convexities and the parasagittal region (in close association with the falx cerebri); tumors in these locations constitute about 50% of all intracranial meningiomas.(1) Meningiomas arising in relation to the sphenoid wings, olfactory grooves, sylvian fissures, and parasellar regions represent about 35%.(2)Less than 10% arise below the level of the tentorium, mainly from the meninges overlying the clivus and petrous pyramid and the leaves and free edge of the tentorium. Tumors arising in relation to the sphenoid wing are frequently flat (en plaque) and tend to invade through both layers of the cranial dura into the adjacent bone, provoking a notable bony reaction with thickening and sclerosis (meningioma bone). Approximately three fourths of meningiomas appear on noncontrast ct as sharply circumscribed, rounded, and sometimes lobulated homogeneous masses of slightly increased density (40 to 50 HU) compared with adjacent brain.Inward buckling of the white matter can be identified in about 40% of meningiomas A hypodense cleft (representing trapped CSF and occasionally blood vessels may be insinuated between the invaginating mass and the invaginated cerebral parenchyma; cystic changes in the arachnoid may also be identified adjacent to the tumor margins. About 10% of meningiomas appear isodense with the adjacent brain on noncontrast ct,and an occasional tumor contains areas of hypodensity that correlate pathologically with foci of ischemic scar, microcysts, or lipoblastic changes.(1) Vasogenic edema of the adjacent cerebral white matter is identified in 50% to 75% of meningiomas.(3) On noncontrast MRl, the majority of meningiomas present a homogeneous appearance similar to that seen on ct. Tumor signal intensity on T1-weighted images tends to approximate that of the adjacent cerebral cortex in about 50% of cases and to be slightly hypointense to cortex in 50%. On T2-weighted images, about 50% are mildly hyperintense relative to adjacent gray matter and 50% are isointense to the cortex On T2-weighted images, comparison of signal intensity of tumor with that of cortex may have histologic correlation; in one reported series, hyperintensity correlated strongly with either syncytial or angioblastic types of meningioma, whereas fibroblastic and transitional meningiomas failed to demonstrate hyperintensity.A minority of meningiomas appear heterogeneous in signal pattern on both Tl- and T2-weighted images because of the presence of intratumoral lipoblastic or cystic changes , calcifications, or prominent vessels.
1-John R.Haaga , CT and MRI of the whole body , fifth edition 2009 , page 99-101. 2-Gold LHA, Kieffer SA, Peterson HO: Intracranial meningiomas:A retrospective analysis of the diagnostic value of plain skull films. Neurology 19:873-878, 1969. 3-Amundsen P, Ougstad G, Syvertsen AH: The reliability of computer tomography for the diagnosis and differential diagnosis of meningiomas, gliomas, and brain metastases. Acta Neurochirurg 41:177-190,1978.