Cavernous Malformation of the Cauda Equina - a Case Report

Background: Cavernous angiomas of the cauda equina are rare vascular malformations; only 15 cases have been reported in the literature. Most cases described adherance to the spinal root of the cauda equina. Case description: A 67-year-old male patient presented with a 1-month history of lower back pain and left sciatica and a 1-week history of exacerbated symptoms. On neurological examination the patient was found to be tender to percussion over the lumbosacral spine, had tenderness over the left sciatic nerve, left hypoesthesia on the L3-4 dermatome with left flaccid lower monoparesis. In addition, he was found to have decreased patellar and Achilles' reflexes on the left. Magnetic resonance imaging (MRI) revealed a heterogeneous enhancing mass obliterating the spinal canal at the L2-3 level and compressing the cauda equina. On operation the lesion was found to adhere to the filum terminale as well as the roots, and was totally resected. Pathological examination confirmed the diagnosis of a cavernous malformation (CM). The patient's pain was quickly resolved after the operation. He remains pain-free with full recovery of motor function and hypoesthesia in the sixth postoperative month. Conclusion: CMs of the cauda equina are extremely rare lesions that may present with lower back pain and sciatica, neurological deficit or subarachnoid haemorrhage. Preoperative differential diagnosis of intradural tumours is not easy in cases without haemorrhage from imaging alone. They can be successfully treated by surgical excision. It is safe to cut the filum terminale or a single root to which the lesion is adherent.