The patient

An 18-year-old man initially presented with the incidental finding five years earlier of a lesion in the left thalamus. He was followed with stable surveillance imaging until 2017 when the lesion started to enlarge. He underwent a stereotactic biopsy confirming juvenile pilocytic astrocytoma.

The challenge

Juvenile pilocytic astrocytomas are typically benign, well-defined tumors of the brain. Often identified in pediatric age groups, these lesions can be cured with surgical resection. Given the critical role of the thalamus in brain function, surgery in this region is frequently avoided. Therefore, thalamic juvenile pilocytic astrocytomas most frequently are treated with radiation therapy rather than with surgery.

The physician

David A. Sun, M.D., Ph.D., neurosurgeon with the Brain Tumor Center and medical director, Norton Neuroscience Institute.

The solution

Minimally invasive laser interstitial thermal therapy was performed. Since the probe is only 2 millimeters wide and is precisely placed using a robotic-assisted stereotactic navigation system, this technique causes minimal injury to the surrounding normal thalamus, in contrast to traditional brain surgery. Energy delivered via the laser heats and kills tumor cells.

Size and shape of laser probe

Laser interstitial thermal therapy surgery.  Yellow (injured) and blue (killed) lines demonstrate heat maps overlaid on tumor. By rotating and moving the laser probe, the heat maps can be contoured to the tumor without injuring the surrounding tissue.

The result

The patient had some mild, transient right-sided weakness that completely resolved. Surveillance imaging continues to demonstrate stable scar and no evidence of tumor recurrence (see Figure 4).  Because the patient has not been exposed to radiation therapy, radiation could be used in the future if the tumor were to recur.

Treatment and results may not be representative of all similar cases.

MRI scans from 2017, one day, six months and two years after laser interstitial thermal therapy surgery without evidence of tumor recurrence.