Hemangiopericytoma - foramen magnum

Case contributed by Ammar Haouimi
Diagnosis almost certain

Presentation

One year history of severe headaches with decreased tongue mobility.

Patient Data

Age: 60 years
Gender: Female

Well-circumscribed lobulated extra-axial mass at the foramen magnum, lateralized to the left, measuring 34 x 28 x 24 mm and extending to the ipsilateral hypoglossal canal. It displays an isosignal to the grey matter on T1, T2 and FLAIR. The post-contrast sequences demonstrate a vivid heterogeneous enhancement with small central cystic areas. The medulla oblongata is compressed and displaced to the right. No significant dilatation of the ventricular system.

Small right parietal lesion with blooming artifact on GE sequence suggestive of cavernoma.

Follow-up MRI performed 2 months after partial resection of the tumor, showing a postoperative cavity with a remnant enhancing soft tissue mass at the hypoglossal canal as well as a partial thrombosis of the left internal jugular vein, sigmoid and transverse sinuses. Subtle dilatation of the 3rd and lateral ventricles.

The left side of the tongue shows areas of high signal due to fatty infiltration consequence of longstanding denervation.

Case Discussion

MRI features of an enhancing extra-axial mass of the foramen magnum, extending to the hypoglossal canal, compressing and displacing the medulla oblongata (schwannoma vs meningioma).

The patient underwent left occipital craniotomy with partial resection of the tumor.  The histopathological exam confirmed the diagnosis of hemangiopericytoma.

Extramedullary tumors of the foramen magnum are relatively rare. The most common are nerve sheath tumors and meningiomas, hemangiopericytoma is very rare in this location.

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