Supratentorial primitive neuroectodermal tumors (PNETs) are rare tumors that 
carry a poorer prognosis than those arising from the infratentorial compartment 
(such as medulloblastoma). The overall prognosis for these patients depends on 
several factors including the extent of resection, age at diagnosis, CSF 
dissemination, and site in the supratentorial space. The authors present the 
first case of a patient with a newly diagnosed supratentorial PNET in which 
cytoreduction was achieved with MR-guided laser-induced thermal therapy. A 
10-year-old girl presented with left-sided facial weakness and a large right 
thalamic mass extending into the right midbrain. The diagnosis of supratentorial 
PNET was made after stereotactic biopsy. Therapeutic options for this lesion 
were limited because of the risks of postoperative neurological deficits with 
resection. The patient underwent MR-guided laser-induced thermal ablation of her 
tumor. Under real-time MR thermometry, thermal energy was delivered to the tumor 
at a core temperature of 90°C for a total of 960 seconds. The patient underwent 
follow-up MR imaging at regular intervals to evaluate the tumor response to the 
thermal ablation procedure. Initial postoperative scans showed an increase in 
the size of the lesion as well as the amount of the associated edema. Both the 
size of the lesion and the edema stabilized by 1 week and then decreased below 
preablation levels at the 3-month postsurgical follow-up. There was a slight 
increase in the size of the lesion and associated edema at the 6-month follow-up 
scan, presumably due to concomitant radiation she received as part of her 
postoperative care. The patient tolerated the procedure well and has had 
resolution of her symptoms since surgery. Further study is needed to assess the 
role of laser-induced thermal therapy for the treatment of intracranial tumors. 
As such, it is a promising tool in the neurosurgical armamentarium. 
Postoperative imaging has shown no evidence of definitive recurrence at the 
6-month follow-up period, but longer-term follow-up is required to assess for 
late recurrence.