Neuroradiology Case of the Week

Case 19

Natasha Buckshee, MD, and P-L Westesson, MD, PhD, DDS

Clinical Presentation: A 25-year-old female presented with headaches. She had a course of radiation therapy many years ago for medulloblastoma.

Radiographic Findings: There are at least five extra-axial mass lesions,
post-surgical changes in the posterior fossa.

Figure 1: Enhancing meningiomas near the right and left cavernous sinus and in the right middle cranial fossa.	Figure 2: Enhancing meningiomas in the suprasellar region and in the left middle cranial fossa.
Figure 3: Enhancing meningioma is seen in the left middle cranial fossa.	Figure 4: Enhancing meningioma is seen in the right posterior frontal region.

Diagnosis: Multiple meningiomas, post-radiation therapy

Discussion:

WHO Classification of Meningiomas:

1. Meningioma (typical benign)
2. Atypical meningioma
3. Anaplastic (malignant meningioma)

   Meningiomas are basically adult tumors occurring between 40-60 years of age. Women outnumber men 2:1. These are extra-axial dural based lesions, 90% are supratentorial.
   Meningiomas typically occur along intradural venous sinuses, at confluence of sutures where arachnoid cell rests occur.
   Multiple meningiomas occur in 1% to 9% of imaged cases, most occur in women. Multiple meningiomas should be differentiated from meningiomatosis, a manifestation of NF-2.

Imaging: Features of an extra-axial mass are widening of the subdural space, grey-white interface buckling, and a cleft of CSF.
   Most meningiomas are iso or slightly hypointense relative to cortex on T1-weighted studies and most fibroblatic/transitional tumors are hypointense relative to gray matter on T2-weighted studies, whereas most meningothelial/angioblastic tumors are hyperintense on T2-weighted studies.
   Radial or sunburst vascular pattern is seen at cerebral angiography.

References:

1. Osborn, Anne G.: Diagnostic Neuroradiology, Mosby, 1994.