Cavernoma of the cauda equina.

BACKGROUND: Cavernomas are benign malformations of the vasculature. In the central nervous system, they are mostly located supratentorially. However, in adults, cavernomas also comprise about 3% of all subdural spinal cord tumors. Notably, cavernomas of the cauda equina are extremely rare, with only 23 cases reported in the literature. Here, we report the 24th case involving a 77-year-old male. CASE DESCRIPTION: A 77-year-old male presented with low back pain for 3 years duration. His history included prostate cancer, skin melanoma, and a sick sinus syndrome requiring a pacemaker. An enhanced computed tomography of the lumbar spine showed an inhomogeneously enhanced, intramedullary mass, located at the L3 level. The patient underwent an L3 hemilaminectomy with gross total excision of the lesion. Macroscopically, the tumor was mulberry-shaped and well demarcated. However, it was strongly adherent to a nerve root of the cauda equina which required resection. The histologic examination was consistent with a cavernoma. The patient subsequently fully recovered without a focal neurological deficit. CONCLUSIONS: Cavernomas of the cauda equina are extramedullary, arise on the inner aspect of the dura, and may be tightly adhered to the nerve roots. To attain gross total excision, the involved nerve may have to be sacrificed; in some cases, this may result in a permanent neurological deficit. Of interest, half of the cauda equina lesions were previously found in patients who had prior radiotherapy; this was not the case in this patient.