Surgically Induced SMART Syndrome: Case Report and Review of the Literature

Introduction: Stroke-like migraine attacks after radiation therapy (SMART syndrome) is a recently described clinical entity characterized by transient hemispheric dysfunction in patients with a history of remote external beam radiation therapy to the brain. Clinically, it may appear that the patient has suffered a devastating stroke and can be associated with seizures as well. Complete neurologic recovery is usual. To date, there have been 25 suspected cases reported in the literature; none were precipitated by intracranial/skull base surgery. We present a case of SMART syndrome diagnosed immediately following craniotomy and resection of metastatic tumor arising from the dura of the floor of the middle cranial fossa after prior gamma knife radiosurgery (GKRS) and whole-brain radiotherapy (WBRT) in the distant past.

Case: A 56-year-old right-handed woman with a history of stage IV infiltrating adenocarcinoma of the right breast was successfully treated with lumpectomy and chemotherapy. Two years from initial diagnosis, her disease progressed to the brain. Approximately 5 years from GKRS to treat multiple intracranial metastases and 2 years following WBRT, she underwent an uncomplicated right frontotemporal craniotomy, anterior temporal lobectomy, and resection of the involved skull base dura for recurrent right middle fossa tumor. On awakening from general anesthesia, she experienced severe head pain, left spastic hemiplegia, and hemi-neglect. Head CT was unremarkable, and she was treated for suspected seizures without improvement. The following day she remained alert and oriented, but still complained of severe right-sided headache. She had left-homonymous hemianopsia, right gaze preference, severe left spastic hemiparesis, left facial droop, and left hypoesthesia. Multiple studies did not reveal an etiology. On postoperative day 2, her headache significantly improved along with partial resolution of her right hemispheric deficits. Brain MRI confirmed gross total resection of the right middle fossa lesion and showed no acute ischemia. She was discharged on postoperative day 7 without focal neurologic deficits.

Discussion: The pathophysiology of the phenomenon is unknown. Previous works have proposed a dysfunction of the trigeminovascular system. In previously reported pediatric cases, radiation boosts to the posterior fossa included the posterior two thirds of the temporal lobe possibly accounting for temporal lobe and trigeminovascular system dysfunction.

The proximity of the enlarging right medial temporal lobe, dural-based lesion to the dura covering Meckel’s cave, and the trigeminal ganglion were noted intraoperatively. These intraoperative observations could localize the SMART syndrome to involvement of the gasserian ganglion and possibly the trigeminovascular system.

Conclusion: This is the first report of a case of SMART syndrome occurring in the acute postoperative period after an uncomplicated neurosurgical procedure. SMART syndrome should be considered in the differential diagnosis of postsurgical patients with remote history of cranial irradiation and significant new neurologic deficits, not otherwise explainable.