Introduction: Although SRS has shown to be successful in a multitude of extradural metastatic tumors causing cord compression, very few cases of intradural treatment have been reported. We present a rare case of an intradural extramedullary metastatic SCLC lesion to the cervical spine resulting in cord compression in an area which had also been extensively pretreated with cEBRT.

Methods: A 53-year-old male with a complicated oncologic history presented with known metastatic SCLC and a new cervical lesion. The patient previously received 36.9 Gy to his cervical spinal cord during treatment for stage III right retromolar trigone oral cavity cancer. He later received 50 Gy at 2 Gy/fraction to his posterior fossa as a part of whole brain radiotherapy. Thus, a total dose exceeding 80 Gy in cEBRT was delivered to his cervical spine prior to his SRS. He then developed severe neck pain without other neurological symptoms. Imaging showed a ventral contrast-enhancing intradural extramedullary mass centered at C1-2 displacing the cervical cord. Neurological exam was intact except for hyperreflexia. He underwent SRS with a dose of 10 Gy in 1 fraction via 7 intensity modulated radiation therapy fields prescribed to the 100% isodose line using 6 MV photons.

Results: Following SRS, the patient had almost complete resolution of his neck pain and remained neurologically intact. His narcotics use also decreased by 66 %. MRI at 3 weeks post-treatment demonstrated complete resolution of his lesion.

Conclusions: Our patient had an intradural metastatic lesion that underwent successful spinal SRS treatment after extensive prior treatment with cEBRT thus making this a unique contribution to the literature. Furthermore, our case illustrates that SRS allows for a single palliative outpatient treatment that was minimally invasive, rapidly effective in terms of both pain and local tumor control, and well tolerated.

Patient Care: Our case is a unique example of spinal SRS being used to treat a cervical intradural lesion in a patient that had been previously irradiated with cEBRT. Furthermore, we add to the literature a rare case of the safe and effective treatment of an intradural lesion treated with SRS, limiting less than 10% of the contoured spinal cord to ≥ 10 Gy in a single fraction.

Learning Objectives: Provide a case example of spinal SRS being used to treat an intradural lesion safely. Describe the benefits of spinal SRS.

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