Proximal nerve root spinal hemangioblastomas: presentation of three cases, MR appearance, and literature review.
BACKGROUND
Hemangioblastomas (HBLs) are relatively uncommon tumors of uncertain histogenesis usually located in the cerebellum or spinal cord. Much less frequently they are identified in extramedullary locations including the filum terminale, proximal nerve roots, or even distal nerves of the peripheral nervous system (PNS). PNS cases not only present diagnostic challenges but also raise interesting questions regarding the common cell of origin for these CNS and PNS neoplasms. Few studies have detailed the neuroimaging characteristics of the rare extramedullary variants.


METHODS
Neuroimaging and intraoperative findings of three recent cases of proximal nerve root HBLs are described. The English language literature on extramedullary HBLs is reviewed and discussed, particularly in regards to magnetic resonance (MR) findings and association with von Hippel-Lindau Syndrome (VHL).


RESULTS
All 3 of our cases had prominent vessels present within the subarachnoid space on MR scans and all lesions enhanced. All were of intermediate or mildly decreased signal intensity on the T1-weighted images before contrast and were either iso- or hyperintense to spinal cord on the T2-weighted images. Two had probable cystic areas on MR, and all had cystic areas on histologic evaluation.


CONCLUSIONS
These neuroimaging characteristics can serve to distinguish HBLs from the more common benign nerve sheath tumors with which they are most frequently confused. Less than half of all extramedullary HBLs are diagnosed in patients with known VHL. It is important to consider HBLs in the differential diagnosis, as they are vascular and have the propensity for causing significant blood loss at surgery.
Department of Radiology, University of Colorado Health Sciences Center, Denver, Colorado, USA.
Edward J
EJ
Escott
B K
BK
Kleinschmidt-DeMasters
Kerry
K
Brega
Kevin O
KO
Lillehei
D000368:Aged; D002420:Cauda Equina / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D018325:Hemangioblastoma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis; D013116:Spinal Cord / Q000473:pathology; D013126:Spinal Nerve Roots / Q000473:pathology / Q000601:surgery*; D013346:Subarachnoid Space / Q000473:pathology; D006623:von Hippel-Lindau Disease / Q000175:diagnosis / Q000473:pathology / Q000601:surgery