Presentation
Headache.
Patient Data
MRI of the brain demonstrates a circumscribed extra-axial right posterior fossa solid mass. t is isointense to the cerebellum on T1 weighted images, and hyperintense on T2. Following contrast administration it vividly and homogeneously enhances. There is no evidence of calcification or hemorrhage. The mass has no relatioship with the intrnal accoustic canal. No significant mass effect over the adjacent right cerebellar hemisphere.
Macroscopy: Labeled "Right posterior fossa tumor". Multiple pieces of roughened grey tissue, 28 x 16 x 16 mm in aggregate. Sectioning shows homogenous firm white-grey tissue. No normal brain identified.
Microscopy: Formalin-fixed, paraffin-embedded sections show a neoplasm comprised of spindled cells arranged in haphazard fascicles and whorls. The cells have plump ovoid nuclei with delicate vacuolated chromatin, conspicuous round nucleoli and tapered eosinophilic cytoplasm; no necrosis. There is an accompanying light lymphocytic infiltrate. Mitoses are rare, numbering fewer than 4 within 10 HPF.
Conclusion: Right posterior cranial fossa tumor: Meningioma, WHO Grade I.
Case Discussion
Given its location apart from the cranial nerves, dural base appearance, and signal intensity, imaging features are consistent with a meningioma.
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