A rare case of cavernous malformation of the cauda equina a case report.

Introduction: Cavernous malformation of the cauda equina is a rare neurosurgical condition. We sought to highlight one of these cases and its resultant diagnosis and management. Additionally, to recommend the need for raised clinical suspicion of these rare masses when an extramedullary lesion is noted on imaging.

Presentation Of Case: A 42-year-old female presented to our institution with a 9-month history of lower back pain. Her examination findings revealed a loss of right ankle jerk reflex. Magnetic resonance imaging (MRI) of her lumbosacral spine demonstrated an intradural, extramedullary tumor involving the cauda equina, at the L4/L5 level. The main differential diagnosis at this time was an ependymoma. An L4/5 laminectomy and resection of the cauda equina mass was scheduled. Intra-operatively, a mulberry - like mass was noted involving a single nerve root. A gross total resection was performed, with resolution of most of her symptoms. Histopathological diagnosis of a cavernous malformation was ascertained.

Discussion: The accurate diagnosis of a cavernous malformation of the cauda equina was only suspected intra-operatively, following gross inspection. Cauda equina masses usually include myxopapillary ependymomas and schwannomas, making this vascular extramedullary lesion low on the possible differentials list. Very few cases have been published in modern literature.

Conclusion: Cavernous malformations of the cauda equina are an extremely uncommon, benign vascular malformation. These malformations have key characteristics on MRI that can aid its differentiation from other intradural lesions. However, because it is so rare, it does not usually make the list of differentials when considering likely extramedullary lesions.