What are the effects of a low frontal falcine meningioma on adjacent brain structures, such as the prefrontal cortex, and what treatment options are available?

Effects of Low Frontal Falcine Meningioma on Adjacent Brain Structures and Treatment Options

Structures Affected by Low Frontal Falcine Meningioma

Low frontal falcine meningiomas primarily compress and displace the prefrontal cortex, particularly the ventromedial prefrontal cortex (vmPFC), leading to cognitive and personality changes that significantly impact quality of life. 1

Specific Neurological Effects

• Prefrontal cortex compression causes impairments in executive function, meta-cognition, decision-making, memory, emotion regulation, and language processing 2

• Ventromedial prefrontal cortex (vmPFC) involvement results in specific personality disturbances including executive disorders, disturbed social behavior, emotional dysregulation, and hypoemotionality 1

• Mass effect on adjacent brain parenchyma with surrounding vasogenic edema occurs in 40-80% of cases, particularly with larger tumors 3

• Cortical buckling and displacement of cortical vessels are characteristic findings that help distinguish meningiomas from other lesions 3

Clinical Presentation

• Psychiatric symptoms are common presenting features, including depressive symptoms, personality changes, and progressive cognitive impairment that may be the only manifestation until tumors become large 4, 5

• Raised intracranial pressure symptoms (headaches, drowsiness, vomiting) occur frequently 3

• Seizures present in up to 30% of cases 3

• Frontal lobe tumors remain "silent" for extended periods, with benign meningiomas compressing frontal lobes producing only progressive personality and intellectual changes until reaching substantial size 5

Treatment Algorithm

For Asymptomatic Small Meningiomas (<30 mm)

Observation with serial MRI surveillance every 6-12 months is recommended for asymptomatic small frontal meningiomas, unless the tumor is easily accessible and poses potential neurological consequences. 6

• MRI with contrast should be performed as the gold standard imaging modality 6
• Observation is particularly appropriate for patients with advanced age or significant comorbidities 6

For Symptomatic Meningiomas

Complete surgical resection with removal of the dural attachment is the optimal treatment for symptomatic frontal meningiomas when feasible. 6

Surgical Approach

• Modern image-guided surgery (frameless stereotaxy) improves precision and reduces surgical side effects 6

• Complete resection aims to remove the tumor with its dural attachment to minimize recurrence risk, though recurrence rates can reach 20% within 25 years even after complete resection of benign meningiomas 6

• Surgical risks must be carefully weighed, as resection of frontal meningiomas involving vmPFC carries significant risk of personality disturbances that strongly correlate with impaired adaptive functioning at long-term follow-up 1

Critical Surgical Consideration

• Twelve of 14 patients with impaired adaptive functioning had vmPFC lesions, and conjoint personality disturbance (specific disturbances in at least 2 of 4 types: executive disorders, disturbed social behavior, emotional dysregulation, hypoemotionality) was present in 12 of 14 patients with impaired adaptive functioning 1

• Early counseling regarding potential personality changes and their implications for adaptive functioning should be provided to patients undergoing anterior skull base meningioma resection 1

Radiation Therapy Indications

External beam radiation therapy (EBRT) is indicated for WHO grade 3 (malignant) meningiomas after surgery and for subtotally resected WHO grade 2 (atypical) meningiomas. 6

• Stereotactic radiosurgery (SRS) is effective for residual or recurrent meningiomas, particularly those <3 cm in diameter 6

• Fractionated stereotactic radiotherapy (SRT) may be preferred for larger meningiomas or those with pre-existing edema 7

• Radiation therapy is not generally indicated for radically resected grade I meningiomas 8

Advanced Treatment Options

• Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin receptor ligands shows promising results for treatment-refractory meningiomas 6

• Somatostatin receptor (SSTR) PET imaging should be performed prior to PRRT to confirm target expression and may be useful when tumor extension is unclear 6

Post-Treatment Surveillance

MRI without and with contrast every 6-12 months is recommended for WHO grade 1 meningiomas, with intervals potentially extended after achieving stable disease status (typically after 5-10 years). 6, 7

• The post-radiotherapy MRI should be considered the "new baseline" rather than the postsurgical MRI for ongoing surveillance 6

• Clinical follow-up should include routine neurological examinations and assessment for personality changes or cognitive decline 7

Common Pitfalls

• Underestimating the impact of frontal meningiomas on quality of life: Even after successful tumor removal, personality disturbances can persist and significantly impair adaptive functioning 1

• Delaying diagnosis: Psychiatric symptoms may be the only manifestation, leading to misdiagnosis as primary psychiatric disorders rather than prompting neuroimaging 4, 5

• Assuming complete resection guarantees cure: Recurrence rates remain significant even after gross total resection, necessitating long-term surveillance 6