Let us talk here about a relatively common brain tumor called meningioma. I shall try to keep this simple yet cover some important aspects. Meningiomas are brain tumors which do not arise from the cells of the brain (as against glioms which arise from glial cells and other tumors which arise from neural cells). As they do not arise from “brain” cells, they actually are extra-axial in location. By that I mean, they are located outside the brain but inside the skull. So meningiomas do not actually “invade” the brain, on the other hand as they grow in size they press on the brain from outside inwards.
This is how meningiomas cause their effects. Depending upon which location the tumor is, as it grows in size it exerts pressure on surrounding structures. Pressure on the surface of the brain may cause seizures (so many patients may present with seizures and when a MRI scan is done the tumor is found), if they are near the optic nerve or tracts patient may present with slowly progressive loss of vision, if near the motor tracts with weakness in the arm and leg, if near the cerebellum with gait and balance problems.
Meningiomas are slow growing tumors and as I stated earlier they usually do not invade the brain (though they may be locally invasive at times and these tumors are called atypical or malignant meningiomas). As these are slow growing, if they are small in size and discovered accidently (as in you went for a MRI for some other reason and a meningioma is found but is not the cause of your symptoms), your doctor may decide not to do anything and just wait and watch and follow you with serial MRI scans. Frequently patients outlive their tumors and die of natural causes without the tumor ever becoming symptomatic. If for some reason it starts increasing in size and becomes symptomatic then a surgical option can be explored.
So now that we know something about these tumors, we can discuss how to treat them. The treatment option pursued depends upon the size and location of the tumor. If the tumor is the right size and in a surgically accessible location, then it is easy take it out surgically if it is symptomatic. However if the tumor is symptomatic but in a surgically inaccessible location like near the optic nerves then other options like sterotactic radiotherapy may be tried. The management decisions need expert opinion and hence one should consult a specialist.
Nitin Sethi, MD
Thank you for sharing your brother’s history with me Franciso, I understand how difficult it must be for you and the entire family. I wish him my very best and please feel free to contact me here if you have any particular questions related to him.
Let me continue a little about the management of brain tumors. Well like I said once we discover a glioma in the brain, we first try to determine its extent in the brain. Tests like CT scan and MRI brain with contrast (dye) are carried out to determine its boundries. Then the question of staging the tumor arises. At times from the MRI itself one can be reasonably sure that this is a malignant glioma or GBM. GBM is one of the few brain tumors, that can spread to the underside of the brain via the corpus callosum and hence gives rise to what we call a butterfly lesion on the MRI (imagine a butterfly with her wings spread out). GBM usually have a lot of surrounding edema which we can see on the MRI again hinting that is a malignant tumor we are dealing with.
Low grade tumors usually are walled off (encapsulated) and do not much surrounding edema. So the next step is trying to stage the tumor and trying to determine its grade. For this reason at times a brain biopsy is done. At the time of the brain biopsy, a frozen specimen is sent to the lab and if the lab gives its initial impression as a tumor, the surgeon might try to debulk the tumor right then and there (that means at the time of biopsy, try to debulk the tumor. This makes sense because the skull is already open and it avoids a second operation).
There is one issue here which is unique for brain tumors like gliomas. The tumor may have one grade on one side and another grade in a different part of the tumor (meaning one part of the tumor may show grade II and the other grade III. To overcome this problem multiple biopsies are taken from different parts of the tumor. The highest grade found is the final grade given to the tumor).
Like I said earlier depending upon the stage of the tumor and its location, the surgeon may or may not be able to remove the entire tumor.
After the biopsy/ surgery patients undergo rehablitation and are then referred to either radiation oncology for radiation or to an oncologist for consideration of chemotherapy. Most of the times all these facilities are available under one roof in a big hospital.
I shall touch on the finer aspects of radiation and chemotherapy in my next post. Its 7.00 pm sat evening NYC, do not have any major plans but do want to get to the gym at some point. Hope all is well in the big world around me.