Role of Surgery in Brainstem Metastasis

Objective: To evaluate surgical management of a single brainstem metastasis. Study Design: Case presentation. Patient and Methods: A 66 years old right-handed male with new onset of slurred speech, imbalance, dizziness, right facial drop, dysmetria, and nystagmus. MRI showed left pons hematoma with irregular enhancement. MRA and angiogram were negative for aneurysm, or AVM. A CT chest showed a single 2cm right lung lesion. Initially improved with steroids but worsened 2weeks after discharge, and his repeated MRI showed enlargement of the pons hemorrhage (2.8cm major diameter) with diagnosis of cavernoma versus hemorrhagic neoplasm, and no signs of hydrocephalus. Results: Performed left anterior petrosectomy (Kawase approach), left ventrolateral infratrigeminal pontine hematoma and cyst fluid evacuation, and lesion biopsy under stereotactic guidance, electrophysiology monitoring (facial nerve, brainstem auditory evoked potentials, and somatosensory evoked potentials), and lumbar drain placement on September 27, 2013. Patient stayed in ICU for4days until lumbar drain removal, discharged to rehab postoperative day6. He experienced a gradual improvement on his balance and face drop. Pathology reported metastatic poorly differentiated adenocarcinoma and received WBRT with a total of 3,000cGy in 10 fractions. Given his decreased size of the lesion and edema, a boost of stereotactic radiosurgery was performed on December 19, 2013 with a total of 12Gy to the margin of the tumor, minimizing brainstem dose. Conclusion: Brainstem metastasis usually carries a poor prognosis, and surgical attempts are avoided due to high morbidity and mortality. In some selective cases of brainstem metastasis, surgical decompression can be safely performed decreasing irreversible damage due to local mass effect.