How is meningioma diagnosed and treated?

Meningioma Diagnosis and Treatment

Yes, you can add images to help with your meningioma question, and MRI with contrast is the gold standard diagnostic imaging modality that should be obtained first. 1

Diagnostic Approach

Primary Imaging

• MRI with contrast is the standard diagnostic test for meningiomas, providing detailed characterization of the lesion and surrounding structures 1
• Typical MRI features include homogeneous dural-based enhancement, presence of a dural tail, CSF cleft between tumor and brain, and possible intratumoral calcifications 1
• Calcifications occur in up to 50% of cases and are more common in pediatric meningiomas 1

Advanced Imaging When Needed

• Somatostatin receptor (SSTR) PET imaging should be obtained when tumor extension is unclear or to differentiate recurrence from post-treatment changes 2, 3
• SSTR PET offers superior detection sensitivity compared to MRI alone for differential diagnosis between meningioma and non-meningioma tissue, assessment of tumor extent, detection of multifocal disease, and distinguishing recurrence from treatment-induced changes 2, 3
• A SUV < 2.3 or SSVRSSS < 3 on SSTR PET excludes meningioma with high probability 2
• Elevated uptake has high positive predictive value for meningioma, though other lesions (brain metastases, gliomas, lymphoma) can occasionally show increased uptake 2

Treatment Algorithm

For Asymptomatic Small Meningiomas (<30 mm)

• Observation is recommended unless the tumor is accessible and poses potential neurological consequences 1
• More than 60% of asymptomatic meningiomas will not grow in size 4
• Radiological characteristics associated with low growth rate include calcifications and hypointense regions on T2-weighted MRI 4

For Symptomatic Meningiomas or Growing Tumors

• Complete surgical resection with removal of dural attachment is the optimal treatment when feasible 1, 5, 6
• Modern surgical techniques including image-guided surgery (frameless stereotaxy) improve precision and may reduce surgical side effects 1
• Surgery should be performed when the meningioma causes neurological symptoms, shows growth on serial imaging, or is accessible with acceptable surgical risk 1

Post-Surgical Management Based on WHO Grade

WHO Grade 1 (Benign):

• No adjuvant radiation therapy needed if completely resected 1
• MRI surveillance every 6-12 months 1
• Recurrence rates can reach 20% within 25 years, necessitating long-term follow-up 1

WHO Grade 2 (Atypical):

• External beam radiation therapy (EBRT) is indicated for subtotally resected tumors 1
• Complete resection alone may be sufficient if Simpson grade I or II resection achieved 7

WHO Grade 3 (Malignant):

• EBRT is indicated after surgery 1
• These tumors have significantly worse prognosis and higher recurrence rates 7

For Surgically Inaccessible or Recurrent Tumors

• Radiation therapy or stereotactic radiosurgery (SRS) are safe and effective alternatives for tumors in critical locations or those demonstrating growth 1, 5
• SRS/RT can be used as primary treatment or complementary to planned subtotal resection for critically located meningiomas 5

Advanced Treatment for Refractory Cases

• Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin receptor ligands should be considered when surgery and radiotherapy are no longer applicable 2, 1
• PRRT remains investigational but shows promising results for treatment-refractory meningiomas with positive SSTR expression 2, 3
• Eligibility criteria include: positive SSTR expression on PET within 2 months, Karnofsky performance status >60% or ECOG 0-2, and no contraindications 2, 3

Important Contraindications to PRRT

• GFR < 40 ml/min/1.73 m² 2
• White blood cells < 3,000/μl with absolute neutrophil count < 1,000/μl, platelets < 75,000/μl 2
• Total bilirubin > 3 times upper limit of normal or albumin < 30 g/l with INR > 1.5 2
• Meningioma with mass effect on brainstem (requires multidisciplinary discussion due to edema risk) 2

Critical Pitfalls to Avoid

• Do not assume all dural-based enhancing lesions are meningiomas - marked T2-hypo- or hyperintensity, absence of dural tail, and dural displacement sign suggest meningioma mimics 1
• Active inflammatory lesions (granulomatous inflammation, neurosarcoidosis) can show increased SSTR PET uptake 2
• Rare meningiomas may have decreased or absent SSTR PET uptake 2, 3
• Increasing SSTR PET tracer uptake during therapy does not necessarily indicate treatment failure, while diminishing uptake may indicate positive response 2

Surveillance Strategy

• For WHO grade 1 meningiomas: MRI without and with contrast every 6-12 months 1
• SSTR PET is useful for distinguishing recurrence from post-treatment changes when MRI is equivocal 2, 3
• Post-radiotherapy MRI should be considered the "new baseline" rather than post-surgical MRI 1