MRI is the best diagnostic examination in the workup of an epidural cavernous hemangioma. Classic MRI findings include a mass within the epidural space that is usually lobulated in contour and may extend into the adjacent neuroforamina. T1-weighted images demonstrate the mass as generally isointense in signal to the adjacent intervertebral disk or isointense with foci of hyperintense signal. T2-weighted images most commonly demonstrate homogeneously increased signal or heterogeneously increased signal. Postcontrast images generally produce avid homogeneous or heterogeneous enhancement.
Some cavernous hemangiomas also have been reported to have a low signal rim on T1-weighted images, T2-weighted images, and postcontrast images[2]; however, a low-signal rim on T2-weighted images is the most common pattern.[2] Some cavernous hemangiomas also have been shown to have a dural tail sign. A dural tail sign is considered to be present if a thin dural enhancement is noted near the mass with a broad angle.[2] If the cavernous hemangioma is located laterally within the epidural space, it may result in widening of the neural foramina.[6]
Intramedullary cavernous hemangiomas occur more commonly than epidural (extramedullary) hemangiomas. Surgical removal of the lesions is currently recommended secondary to the risk for hemorrhage, which has been estimated at approximately 1.4%-4.5% per year. However, if patients have a history of hemorrhage, the risk for rebleeding is estimated at 66% per year.[3] Preoperative hemorrhage of the cavernous hemangioma has been associated with a worse postoperative prognosis secondary to damage to the cord from mass effect from the hemorrhage.
Even in the absence of hemorrhage, intramedullary and extramedullary cavernous hemangiomas have been associated with progressive clinical deterioration suggesting that observation is less favorable in most cases. Postoperatively, extramedullary cavernous hemangiomas have been associated with a better clinical outcome than intramedullary cavernous hemangiomas. This is assumed to be secondary to the fact that intramedullary cavernous hemangiomas grow within the spinal cord and, therefore, require a myelotomy for removal, whereas an extramedullary cavernous hemangioma is located outside the spinal cord and can be removed while leaving the cord intact.
In one study, of 290 reported cases of patients who underwent surgery to remove an intramedullary cavernous hemangioma, 62% improved, 29% stayed the same, and 9% reported worsening symptoms following surgery.[3] Of the 60 reported cases of patients who underwent surgery to remove an extramedullary cavernous hemangioma, 90% improved, 8% stayed the same, and 2% reported worsening symptoms following surgery. In a Japanese case report, microsurgical resection of a thoracic epidural cavernous hemangioma that extended into the neuroforamen was successful in an elderly male who had presented with neuropathic pain and bilateral lower limb muscle weakness.[7] Following a partial laminectomy and limited medial foraminotomy, surgeons resected the tumor within the neuroforamen without the necessity of a spinal stabilization procedure.
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