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Spinal subdural enhancement after suboccipital craniectomy
D W Shaw1, E Weinberger, D K Brewer
1Department of Radiology, University of Washington, Seattle, USA.
Insights
Transient intraspinal subdural enhancement after posterior fossa tumor resection can mimic tumor spread on MRI. This enhancement is typically benign and resolves over time, reducing false-positive diagnoses of metastatic disease.
Area of Science:
- Neuroradiology
- Pediatric Oncology
- Neuro-oncology
Background:
- Suboccipital craniectomy for posterior fossa tumors is common in children.
- Spinal MR imaging is used for staging and detecting metastatic disease.
Purpose of the Study:
- To characterize transient intraspinal subdural enhancement after posterior fossa tumor resection.
- To differentiate this enhancement from subarachnoid tumor spread on MR images.
Main Methods:
- Retrospective review of 10 pediatric patients' imaging and medical records.
- Inclusion of one additional case from another institution.
Main Results:
- Four of 10 patients showed intraspinal subdural enhancement 6-12 days post-surgery.
- Enhancement resolved in follow-up MR studies without treatment.
- CT myelography in one patient showed no subarachnoid lesions.
- No metastases developed during 2.5-3.5 year follow-up.
Conclusions:
- Intraspinal enhancement is likely extraarachnoid/subdural and transient.
- Awareness of this finding reduces false-positive metastatic disease diagnoses.
- Preoperative spinal staging is recommended for these patients.
Purpose:
To characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection.
Methods:
Radiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review.
Results:
Intraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.