How should an incidentally discovered 6 mm ossified meningioma on the left frontal convexity in an asymptomatic adult be managed?

Management of Incidentally Discovered 6mm Ossified Meningioma

For an asymptomatic adult with a 6mm ossified meningioma on the left frontal convexity, observation with serial MRI surveillance is the recommended management approach. 1

Initial Management Strategy

Observation is appropriate for this lesion because it meets the criteria for conservative management: the tumor is small (<30mm), asymptomatic, and located in an accessible but non-critical area. 1, 2

Rationale for Observation

• The National Comprehensive Cancer Network specifically recommends observation for asymptomatic meningiomas less than 30mm in diameter. 1
• At 6mm, this lesion is well below the threshold requiring intervention, even in accessible locations. 1
• Radiological surveillance is a valid option for low-grade asymptomatic meningiomas, as the majority of meningiomas are benign with slow growth patterns. 3

Surveillance Protocol

Implement the following MRI monitoring schedule:

• Obtain baseline MRI with and without contrast within 2 weeks to establish accurate measurements and characteristics. 1
• Perform follow-up MRI with contrast every 6-12 months initially for WHO grade 1 meningiomas. 1, 2
• After achieving stable disease (typically 5-10 years), surveillance intervals can be extended. 2

Key Imaging Considerations

• MRI with contrast is the gold standard for meningioma surveillance, with post-contrast T1-weighted imaging being the most important sequence. 1, 2
• Calcifications (ossification) occur in up to 50% of meningiomas and are best visualized with susceptibility-weighted imaging (SWI) sequences. 1
• The ossified nature of this meningioma does not change the surveillance approach but may be relevant if future surgery becomes necessary. 4

Indications to Transition from Observation to Intervention

Surgery should be considered if any of the following develop:

• Development of neurological symptoms attributable to the lesion (headaches, seizures, focal deficits). 1, 2
• Evidence of tumor growth on serial imaging studies. 1
• Patient develops symptoms even without documented growth, as frontal convexity meningiomas can cause subtle cognitive changes. 5

Special Considerations for Frontal Convexity Location

• Frontal convexity meningiomas may cause subtle higher brain function disturbances even when "asymptomatic," which can improve after resection. 5
• However, at 6mm, the risk of such effects is minimal and does not justify prophylactic surgery. 1
• Seizures occur in up to 30% of symptomatic meningiomas, particularly those in convexity locations. 6, 7

Surgical Considerations if Intervention Becomes Necessary

If the lesion grows or becomes symptomatic:

• Complete surgical resection with removal of dural attachment is the optimal treatment when feasible. 1, 2
• The frontal convexity location is generally accessible with acceptable surgical risk. 1
• Ossification may interfere with surgical technique and requires specialized consideration, though complete removal remains the goal. 4
• Modern image-guided surgery (frameless stereotaxy) improves precision and reduces complications. 2, 7

Critical Pitfalls to Avoid

• Do not assume all enhancing dural-based lesions are meningiomas - brain metastases, gliomas, and primary CNS lymphoma can mimic meningiomas, though the ossification makes meningioma most likely. 2, 7
• Do not rely on CT alone - while CT can detect calcified meningiomas, MRI is significantly superior for characterization and surveillance. 1
• Do not dismiss subtle cognitive or personality changes - frontal lesions can cause higher brain function disturbances that patients may not spontaneously report. 5
• Do not perform prophylactic radiation therapy - radiation is not indicated for asymptomatic, unresected grade 1 meningiomas. 2, 3

Patient Counseling Points

• Emphasize that most meningiomas are benign and grow slowly, with many never requiring treatment. 3, 8
• Explain that recurrence rates for completely resected benign meningiomas can be up to 20% within 25 years, underscoring the importance of long-term follow-up if surgery eventually becomes necessary. 1
• Advise the patient to report any new headaches, seizures, weakness, or cognitive changes immediately rather than waiting for scheduled imaging. 7