American Journal of Neuroradiology

Case of the Week

Section Editors: Matylda Machnowska¹and Anvita Pauranik²
¹University of Toronto, Toronto, Ontario, Canada
²BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada

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February 4, 2021

Extradural Spinal Hemangioblastoma

Background:
- Spinal hemangioblastoma (SH) is a low-grade vascular neoplasm that primarily occurs in the spinal cord.
- Sixty percent are intramedullary, 11% intra- and extramedullary, 21% intradural extramedullary, and 8% extradural.
- Most common in the thoracic spine, followed by cervical, and lastly lumbar
- Most SHs occur sporadically. There is an association with von Hippel-Lindau disease (VHLD) (approximately one-third of cases).
Clinical Presentation:
- Primary symptoms include pain, proprioceptive sensation disturbance of position and vibration, motor weakness, and bowel and/or urinary dysfunction.
- The distribution of sensorimotor symptoms depends on the location of the lesion. There are no differences in symptoms between patients with and without VHLD.
Key Diagnostic Features:
- Well-demarcated T2-weighted hyperintense tumors with adjacent bone remodeling (not erosion—these are low-grade tumors)
- Peritumoral edema (not always present)
- Larger tumors demonstrate vascular flow voids and intense enhancement on MRI.
- Angiographic findings include enlarged feeding arteries, densely staining tumor nodule, and evidence of AV shunting.
Differential Diagnoses:
- Predominantly based on location of the tumor on imaging
- Arteriovenous malformation: Similar presence of vascular flow voids and associated angiographic findings of prominent feeding arteries and shunting. Presence or absence of a well-defined mass is the key point of differentiation.
- Spinal paraganglioma: These tumors are typically located in the intradural extramedullary compartment and can thus be difficult to distinguish from extramedullary SH. These tumors demonstrate similar T2 hyperintensity, congested/ectatic vessels, and a low-signal-intensity rim or “cap sign.” A tumor outside the intradural extramedullary compartment is unlikely to be a paraganglioma and could thus remove this item from the differential.
- Malignant peripheral nerve sheath tumor (MPNST): Aside from pain, masses greater than 2–6 cm with irregular borders plus a history of rapid growth define MPNSTs. These lesions also typically demonstrate more rapid and infiltrative growth patterns, intratumoral cysts, perilesional edema, and peripheral enhancement. Additionally, while MPNSTs are highly vascular tumors, the significant AV shunting seen with SH is rarely seen in lesions other than AVM.
- Neurofibroma: Typically benign and manifests as multiple tumors. Benign and more slow-growing with more indolent clinical symptoms. CT findings are well described and include hypoattenuation with central enhancement or “target” appearance, or the classic “dumbbell lesion” consisting of partly intradural and partly extradural tumor. MRI signal intensities consistent with higher degrees of anaplasia can be used to distinguish neurofibroma and MPNST, but these lesions appear generally radiologically outside of the differences highlighted here.
Treatment:
- The treatment of choice for symptomatic spinal hemangioblastoma is surgical removal. Most tumors are amenable to resection with preservation of neurologic function.