Haemangiopericytoma

Case contributed by Dr Bruno Di Muzio

Presentation

Sudden right-sided weakness.

Patient Data

Age: 62-year-old
Gender: Male

ASNR 2016: This case was submitted as part of the American Society of Neuroradiology (ASNR 2016) Case Of The Day competition, in collaboration with Radiopaedia.org. 

CT

CT Brain

CT Brain demonstrates a soft tissue mass expanding and eroding the left parietal bone and extending intracranially compressing the adjacent left temporal and parietal lobes. There is an expressive mass effect characterised by vasogenic oedema, compression of the left lateral ventricle and midline shift to the right. The mass vividly enhances after contrast administration. The remainder brain is unremarkable. Further assessment with MRI is advised.

MRI

MRI Brain

The large and bilobed extra-axial mass is again demonstrated extending into destroying left parietal bone and with an intra dural component that severely indents the left frontoparietal lobe.  At the deep margin where brain parenchyma is indented, there are 2 cystic components. There is marked left frontoparietal vasogenic oedema which extends inferiorly along internal and external capsules. The lesion has heterogeneous low and intermediate T2 signal and demonstrates a diffuse vivid enhancement. No internal diffusion restriction. A few foci of susceptibility artefact reflect calcification or blood product. There is linear dural enhancement extending along the displaced and distorted dura. There is 12 mm of midline shift toward the right at the level of the foramen of Monro and uncal herniation with the distorted region of the midbrain. No tonsillar herniation. Dilated entrapped left temporal horn. No distant areas of pathological enhancement. A few small T2 hyperintense white matter foci are compatible with expected age-related changes of chronic small vessel ischaemia.

Conclusion: Severe mass effect due to a large left extra-axial mass with intraosseous and intradural components. The main differential diagnosis is between metastasis, meningioma, and haemangiopericytoma.

Pathology

Histology

MICROSCOPIC DESCRIPTION: The sections show a variably hypercellular spindle and epithelioid cell tumour with a broad dural attachment. The tumour is intensely vascular and, in many areas, vessels have "staghorn" profiles. Tumour cells show moderate nuclear pleomorphism and are dispersed in a fibrous stroma. Occasional mitotic figures are identified (3/30HPF). No areas of necrosis are identified. Infiltration into bone is seen in specimen 2. There is no evidence of brain invasion.

Inmmunohistochemistry shows strong staining in tumour cells for bcl-2 and MIC2 (CD99) and moderate staining for CD34. Immunostaining for epithelial membrane antigen (EMA) and progesterone receptor (PgR) is negative.

The features are of solitary fibrous tumour/haemangiopericytoma spectrum tumour (WHO Grade II). The topoisomerase labelling index is approximately 1%.

DIAGNOSIS: Bone/skull/brain tumour: Solitary fibrous tumour/haemangiopericytoma spectrum tumour (WHO Grade II).

SUPPLEMENTARY REPORT: Sections of decalcified tissue show permeation of bone by tumour extending to but not breaching the outer table.

Case Discussion

This case demonstrates an extra-axial mass that expands and partially destroys the left parietal bone and causes an expressive mass effect over the adjacent brain. 

The main radiological differentials to be considerd are meningioma, haemangiopericytoma and a lytic skull metastasis. The latter less likely due the homogeneous signal and enhancement in a big soft tissue mass. 

After surgery, histology study confirmed the diagnosis of haemangiopericytoma

It is hard if not impossible to distiguish haemangiopericytoma from meningiomas on imaging. Meningiomas are less likely to erode adjacent bone though. 
 

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Case information

rID: 42359
Case created: 18th Jan 2016
Last edited: 29th Feb 2016
Tags: asnr2016, rmh
Inclusion in quiz mode: Included

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