Cauda Equina Cavernoma at level L1 Concurred with Intervertebral Disc Herniation at Level L5-S1: A Case Report of Misdiagnosis.

Abstract

Vascular tumors show an extremely wide spectrum of morphologic appearances and clinical behavior. Hemangiomas or cavernomas occupy a gray zone and, because of their mass effect and localized nature, are designed frequently as tumors. Cavernous angiomas are uncommon vascular malformations found in all locations within the central nervous system. Incidence reported lie between 0.02 and 0.9%. Within the spinal cord they are most likely intramedullary and they account for 5-12% of all vascular lesions [1], [3]. Cauda equina is the least frequent site [3]. We show a case of misdiagnosis of a 45-year-old man complained of low back pain six months prior to surgery. A magnetic resonance imaging (MRI) scan revealed an L5-S1 bulky disc herniation extruding to the center of the lumbar spinal canal and compressing the thecal sac and the L5 left nerve root. An intracanal structure, at L1 level, was found and a tumor was suspected. A contrast enhanced MRI showed a round mass of 4mm diameter, slightly enhanced by gadolinium on T1W scans. Radiological diagnosis was a schwannoma. After neurosurgical and radiological evaluation, the patient underwent to the surgery. Tumor was pathologically confirmed to be cavernoma. Post-surgery, symptoms decreased and the hypoesthesia recovered completely. There were no post-operative complications. There are very few descriptions (to our knowledge, < 30 cases [2] are documented in the literature) of intradural extramedullary cavernomas of the cauda equina. The most frequent presentation of cavernomas of cauda equina is between L1 and L3 [2,3], sometimes extended to more than one level. In our case the level was T12-L1, extended more in L1, on the right side, the presentation was sub-acute. Surgical intervention was direct to the disc herniation, secondary to the exeresis of the tumor. Because of intra-operating and histological findings, the acute presentation was more to be appointed to the cavernomas lesion, so the surgery we performed was precise and effective due the radiological misdiagnosis and sub-acute clinical manifestation. In our opinion their management should be a complete microsurgical removal of the tumor not only to obtain a neurological improvement in symptomatic cases, but also to achieve a definitive diagnosis.