Solitary fibrous tumor (hemangiopericytoma)

Case contributed by Pablo Diluca
Diagnosis certain


4-week history of blurred vision and headache.

Patient Data

Age: 20 years
Gender: Female

Non-Contrast CT


Large extra-axial lobulated and hyperdense mass centered at the torcula and transverse sinuses.

MRI perfomed 6 month after CT scan.

The enlarging extra-axial lobulated mass is again demonstrated. It grows deep into the torcula, straight, transverse and superior longitudinal sinuses compressing the adjacent cerebellum and occipital lobes. 

The lesion has heterogeneous low and intermediate T2 signal and demonstrates a diffuse vivid enhancement. No areas of internal diffusion restriction.

At spectroscopy there is a high choline concentration, low NAA and a tiny lactate/lipid peak.

The main differential diagnosis were metastasis, meningioma, lymphoma and hemangiopericytoma.

Hypervascular blush in posterior region dependent on pial and dural branches of the posterior circulation and branches of the external carotid arteries, preferably on the right side through the occipital arteries.



MICROSCOPIC DESCRIPTION:  Celullar proliferation with nidus of small, hiperchromatic nuclei cells, and high mitosis. Some areas of necrosis are identified. 

Inmmunohistochemistry shows strong staining in endothelial cells and perinuclear for CD34.

Negative immunostaining for epithelial membrane antigen (EMA). KI 67 is positive.

DIAGNOSIS: Anaplastic Hemangiopericytoma (Solitary Fibrous Tumor/Hemangiopericytoma) WHO Grade III.

Case Discussion

This case demonstrates an extra-axial mass that expands and infiltrates the torcula, venous sinuses, leptomeningeal space and erodes the adjacent bone.

The main radiological differentials to be considered are metastasis, meningioma, hemangiopericytoma and lymphoma. The latter less likely due the inhomogeneous signal and enhancement in a big soft tissue mass. 

After surgery, histology confirmed the diagnosis of a solitary fibrous tumor of the dura (hemangiopericytoma). 

It is hard if not impossible to distinguish hemangiopericytoma from meningiomas on imaging. Meningiomas tend not to infiltrate leptomeningeal space and tend to thicken the adjacent bone.

Although invasion of the sinuses by a tumor, especially by a meningioma, can occur, mass lesions residing exclusively within the venous sinuses are rare. 


I would like to thank Dr. Hector Lambre, Jorge Chudyk, Pedro Lylyk, Ana Lia Taratuto and all Residents and Radiology Department staff of Clínica La Sagrada Familia.


Note: at the time of diagnosis this tumor was known as a hemangiopericytoma. Under the 5th Edition (2021) of the WHO classification of CNS tumors, it is now considered a solitary fibrous tumor of the dura. 

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