Case Studies Series: Brain Stem Tumor

This child is a 6 year-old who presented with progressive right-sided weakness. The weakness was initially subtle with some dragging of the right foot but it progressed to the point that he was falling and eventually could not walk. The weakness affected his face, arm, and leg. He was sent for an MRI and based on the results of the MRI, sent to me for an evaluation.

The MRI, unfortunately, showed a large tumor in the left side of his brain stem. The tumor extended from the midbrain (superiorly) to the pons (inferiorly). Brain stem tumors in this age group can run the spectrum from very benign tumors to very malignant tumors. Some of these malignant brain stem tumors are so aggressive that they are invariably fatal.

We could not be sure which type of brain tumor he had. We discussed treatment options with his parents. The first step needed to be surgery.

The goal of surgery was two-fold. First, we needed tissue to make a diagnosis of the type of tumor, and second we needed to resect the lesion. The goal was a gross total resection (GTR) of the lesion. If the tumor was benign, then a GTR would be curative. If it was more aggressive, then a GTR can improve long-term survival. In malignant tumors, however, our goal is for a GTR only if we can do it safely. Since these malignant tumor have a poor prognosis, we are more cautious so that we don’t cause a neurological deficit. In these cases, the extra amount of tumor resected will not result in an improved outcome.

He went to surgery and I approached the tumor through the floor of the 4th ventricle. The initial pathology during surgery indicated that this was an astrocytoma but no grading (level of aggressiveness) could be provided.

I was concerned during surgery that this was going to be a malignant tumor based on the way it looked under the microscope. Therefore, I stopped the resection rather than risk a neurological deterioration. He woke up with some eye movement abnormalities, specifically that his eyes did not tracking symmetrically. His hemiparesis was actually better.

I waited for the pathology to be final. We could not get a definitive diagnosis and the specimens were sent to multiple other centers so that we could get more opinions regarding the pathology. None of the pathologists could grade the tumor. Based on this, we reviewed the options with the family and our oncology team. We decided to go back and get a GTR.

He had a revision surgery about a month after his primary surgery. I was more aggressive this time around and achieved a GTR. He woke up from surgery completely unchanged neurologically and his imaging showed a GTR.

His repeat pathology was again indeterminate. We were uncertain of the grade.

After discussing the treatment options, he was sent for proton beam radiation to the resection cavity so that we minimize the radiation injury to his brain. He is now 9 months out from his initial surgery. He has very minimal weakness on the right side (much better that when he first presented) and minimal double vision (that is almost back to normal).

His scans show no residual or recurrent tumor. I can’t say that he is cured but he is doing very well in terms of his neurological status and tumor control. I am hoping that he won’t have a recurrence.