11.5.12  Residual/Recurrent Tumors

11.5.12.1\ Discussion

The risk of residual or recurrent spinal tumor depends largely on the type of tumor and treatment. In general, postoperative imaging evaluation should cover the entire length of the surgical approach, since recurrence can occur anywhere along this path, especially at the original tumor margins. Gross total resection is often feasible for schwannomas, meningiomas, paragangliomas, myxopapillary ependymomas, ependymomas, and hemangioblastomas. Although astrocytomas are typically infiltrative neoplasms, radical resection can result in long progression-­

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free survival. Nevertheless, follow-up imaging is often performed to monitor for residual/recurrent tumor. MRI with contrast is generally the modality of choice for evaluating residual/recurrent spinal tumor (Fig. 11.111). Initial postoperative changes with enhancement can sometimes mimic residual tumors. Follow-up MRI can help differentiate between these two processes, whereby residual tumor may persist and even grow. Comparison with prior imaging is also very useful. It is important to image along the entire length of the surgical approach for assessment of tumor recurrence, which may include the abdomen or chest if an anterior approach has been implemented.

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Fig. 11.111  Residual tumor. The patient has a history of conus medullaris schwannoma resected via a posterior approach. Preoperative sagittal post-contrast T1-weighted MRI (a) shows a heterogeneously enhancing mass that involves the proximal cauda equina. Postoperative sagittal post-contrast T1-weighted MRI (b) obtained 1 week after

surgery shows a tiny focus of enhancement adjacent to the conus medullaris (arrow). Sagittal post-contrast T1-weighted MRI obtained 6 months later (c) shows interval increase in size of the enhancing nodule adjacent to the conus medullaris (arrow), but resolution of the cauda equina nerve root enhancement