July 3, 2010

Meningioma

Figure 1: Axial unenhanced CT image of the brain shows an isodense mass in the left posterior fossa with minimal, if any, mass effect.
Figure 2: Axial contrast-enhanced T1W MR image shows a large homogeneously enhancing extra-axial mass (star) near the left petrous bone overlying the sigmoid venous sinus (arrow).


Facts: Meningioma
  • Tumors of meningeal cells (typically arising from meninges but can also be found in the choroid plexus, tela choroidea and arachnoid villi); therefore meningiomas can be seen in the meninges, spinal canal, intraventricular, and pineal regions
  • Common, greater than 20% of all primary intracranial neoplasms
  • Female:male = 3:2 to 2:1; mostly in late middle age
  • Pathology: benign, atypical and malignant
Imaging Features
  • Homogeneous, lobulated, well-circumscribed mass with uniform dense enhancement following contrast administration
  • Common locations: parasagittal > convexity > sphenoid ridge
  • High attenuation on unenhanced CT, iso- to mildly hypointense on T1W MR images
  • May calcify in up to 1/4 of all cases, best seen on CT. Calcifications can be microscopic, punctate, large, peripheral or central. Malignant meningiomas rarely calcify.
  • Hyperostosis can be seen in up to 1/2 of cases that meningiomas are immediately adjacent to the bone. Common in 'en plaque' meningioma
  • Uncommon to have bone destruction (if pure destruction think of metastasis, sarcoma or myeloma)
Our case: benign meningioma overlying the sigmoid sinus without invasion. It is important to note if the meningioma is adjacent vascular structures for optimal surgical planning.

References:
1. Drevelegas A. Imaging of brain tumors with histological correlation, 2002.
2. DeAngelis LM, Gutin PH, Leibel SA. Intracranial tumors: diagnosis and treatment, 2002.

1 comment:

demony granger said...

This is very good information.i think it's useful advice. really nice blog. keep it up!!!

meningioma

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