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Meningeal hemangiopericytoma

Meningeal hemangiopericytomas (now reclassified as grade 2-3 solitary fibrous tumors of the dura) present as large, locally aggressive dural masses, typically in younger adults (30-50 years) with mass effect symptoms (headache, seizures, focal neurological deficit) and potential for systemic metastasis in up to 20% of cases.

Key Images

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Look For First
  • Large, highly vascular dural mass with vivid enhancement and lobulated contour in a younger adult
  • Multiple flow voids on MRI (distinguished from meningioma's spoke-wheel pattern) and frequent adjacent bone erosion without hyperostosis
  • Narrow base of dural attachment with dural tail sign (more common in grade II), distinguishing it from broad-based meningiomas
Key Image Findings
  • CT shows vivid enhancement, bone erosion without hyperostosis or calcification, and highly vascular appearance
  • MRI T1: isointense to grey matter with heterogeneous vivid gadolinium enhancement
  • MRI T2: isointense to grey matter with multiple flow voids reflecting high vascularity (not the central spoke-wheel vascular pattern of meningioma)
  • Frequently supratentorial masses with lobulated contours, though posterior fossa location in posterior occipital region is another common site
  • Adjacent brain edema is frequently present, indicating mass effect
  • MR spectroscopy shows high myoinositol and absent alanine peak (opposite of meningioma pattern)
  • DWI/ADC shows intermediate restricted diffusion (less than meningioma) with minimum ADC ~1100 (±130) × 10⁻⁶ mm²/s
  • DSA demonstrates external carotid, internal carotid, and vertebral artery supply with highly vascular appearance, corkscrew arteries, fluffy tumor stain, and lack of early draining veins
Differential Diagnosis
  • Meningioma: presents in older patients (>50 years), has smoother contour, central spoke-wheel vascular supply, broad dural attachment, causes hyperostosis (hemangiopericytoma does not), and is very unlikely to metastasize or erode bone
  • Other dural masses including lymphoma, metastases, and dural schwannomas should be considered but differ in location, enhancement pattern, and clinical context
Discussion

Hemangiopericytomas are now definitively classified as grade 2-3 solitary fibrous tumors of the dura (WHO 2021), sharing the characteristic NAB2-STAT6 gene fusion confirmed by immunohistochemistry

These are highly aggressive tumors with high recurrence risk, necessitating total surgical excision combined with adjuvant radiotherapy

The high vascularity and propensity for bone erosion distinguish them from the more common meningioma, making preoperative DSA and embolization critical for surgical planning

Up to 20% of hemangiopericytomas metastasize systemically (liver, lung, bone), unlike meningiomas, requiring long-term surveillance

The presence of multiple flow voids on MRI and intermediate DWI restriction help differentiate this entity from meningioma, which shows spoke-wheel vascularity and greater DWI restriction

STAT6 positivity and CD34 positivity on immunohistochemistry confirm diagnosis, whereas EMA positivity favors meningioma

Reporting Pearls

Report the size, location, and degree of enhancement, and specifically describe the pattern of vascularity (multiple flow voids vs. spoke-wheel) along with presence/absence of bone erosion, broad versus narrow dural attachment, and presence/degree of adjacent edema. Recommend preoperative DSA for assessment of vascular supply and dural venous sinus involvement to guide surgical and embolization planning.

Pitfalls
  • Confusing hemangiopericytoma with the far more common meningioma based on similar imaging appearances; key distinguishing features include bone erosion without hyperostosis, multiple flow voids, narrow dural attachment, and younger patient age
  • Missing the spoke-wheel central vascular pattern of meningioma versus the peripheral multiple flow voids of hemangiopericytoma on MRI
  • Underestimating aggressiveness and recurrence risk; hemangiopericytomas require total resection plus radiotherapy unlike many meningiomas
  • Not recognizing the metastatic potential (up to 20% systemic metastases); long-term imaging surveillance of liver, lungs, and bones is essential
Source: Reference source

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