Meningioma/divalproex

My 81-year old mother was diagnosed in April with a meningioma, discovered during evaluation of an unrelated ear problem.  A follow-up MRI in July showed no significant change.  It's a 4 x 4 x 3.5cm extra-axial lesion in the right frontal lobe.  There is a cerebral spinal fluid collection between the mass and the frontal lobe, and there is a relatively broad base of the mass adjacent to the right frontal bone.  There is no significant edema surrounding the mass.  The ventricles are normal in size and there is no evidence of hydrocephalus.  The paranasal sinuses appear relatively clear.  No significant cerebellar tonsillar ectopia was identified.  An EEG taken in May was normal.

She is, and always has been, asymptomatic.  She is in good health, active, happy, and enjoying life.

In addition to continued observation, a neurosurgeon recommended that she start on divalproex 500mg bid as a prophylactic anticonvulsant.  Her neurologist initially stated that she didn't need this, but then changed his mind in the middle of the conversation and agreed with the recommendation.  (Leaving her a bit confused, I'm afraid.)  I've read the abstract from the study conducted by Glantz et. al. at Brown, which notes that "prophylactic anticonvulsants are widely advocated despite a lack of convincing evidence of their efficacy in preventing first seizures."  (Neurology; VOL 46, ISS 4, 1996, pp 985-91.)  Their hypothesis that such treatment provides a reduction in the frequency of first seizure was actually rejected by the results of the study, and they concluded that "anticonvulsant prophylaxis with divalproex sodium is not indicated for patients with brain tumors who have not had seizures."

My primary question is with the respect to the advisability/necessity of starting on the divalproex.  It's not clear to us that there is a really a compelling reason for it.

Secondly, could you comment on the decision to observe the mass at this time, as opposed to surgery.

Thanks very much.

[CCF Neuro[P] MD, RPS]

Dear Kenneth:

Sorry about your mother.  What we know about meningoma is that most of the time it is very benign.  Most of the time we find it accidently while looking for something else.  There is not much to be done but watch whether it grows or not.  Most of these are very slow growing and are definitely not a problem.  Whether to take VPA or not to prophylax against seizures is something that has two points of view, we do not treat.  If seizures occur then we would of course treat the seizures. The vast majority of people have no seizure event nor do they ever require surgery from the meningoma growing and causing bad effects.

This is our view of things at the Cleveland Clinic.  I hope this helps you manage your mother's problem.

Sincerely,

CCF Neuro MD