Hemangiopericytoma

Case contributed by A.Prof Frank Gaillard

Presentation

Headache

Patient Data

Age: 70 years
CT

A large hyperdense lobulated vividly enhancing extra-axial mass is seen adjacent to the falx. 

MRI

Large right extra-axial posterior parafalcine mass is heterogeneous, but of similar signal intensity to brain parenchyma on T1 and T2-weighted imaging. Slightly increased signal on FLAIR. Diffuse homogeneous bright enhancement with central nonenhancing T2 hyperintense component. There is markedly lobulated surface contour.

The mass compresses the trigone of the right lateral ventricle, displaces and compresses the splenium of the corpus callosum, and compresses the medial right occipital lobe. There is abnormal T2 hyperintensity in the white matter of the right parietal, posterior right frontal, and right occipital lobes. There are large vessels along the surface of the mass.

Markedly elevated relative cerebral blood volume. MR spectroscopy demonstrates marked elevation of choline, depletion of creatine and NAA. No alanine peak (if present, would favor meningioma).

Conclusion: Large right parafalcine extra-axial mass likely to represent a hemangiopericytoma with the obvious differential of a meningioma.

Case Discussion

The patient went on to have surgery.

Histology

Paraffin sections show a densely cellular, dural-based tumor. Tumor cells have pleomorphic round, oval and elongated nuclei with vesicular chromatin and a variable amount of cytoplasm and are arranged in solid sheets in a fibrous stroma. Formation of thin-walled "staghom" vascular channels is noted in many areas. Five mitotic figures are identified in 20 high power fields. There are several foci of geographic necrosis. One of these is surrounded by a palisaded arrangement of tumor cells. No evidence of brain invasion is seen.

Immunohistochemistry results show tumor cells stain: STAT6+ (focal), Co99+, BCL2+, EMA-, PR-, SST R2- and Co34-. The Topoisomerase proliferation index is approximately 15%.

FINAL DIAGNOSIS: Hemangiopericytoma/solitary fibrous tumor (WHO Grade II).

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Case information

rID: 61045
Published: 15th Jun 2018
Last edited: 15th Jun 2018
Inclusion in quiz mode: Included

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