Cauda equina syndrome after spinal epidural steroid injection into an unrecognized paraganglioma.

Objective: Clinically significant spinal hemorrhage is an extremely rare but potentially devastating complication of spinal epidural steroid injection. We report a rare case of cauda equina syndrome after spinal epidural injection that inadvertently penetrated an unrecognized spinal paraganglioma.
Methods: The clinical records for a patient presenting with cauda equina syndrome were retrospectively reviewed. A literature search was performed to identify reports of cauda equina syndrome in patients undergoing spinal epidural steroid injection, as well as recent large series describing complications associated with these injections.
Case Report: A 37-year-old man presented to our emergency department with severe low back pain radiating bilaterally to the lower extremities and urinary incontinence. His pain had greatly intensified 1 day after spinal epidural steroid injection. He had a 1-year history of low back pain diagnosed as disk herniation and managed conservatively but had experienced recent onset of a similar pain and new onset of nocturnal back pain causing sleep disturbance. Epidural injection had been administered based on the earlier diagnosis of disk herniation. Examination using magnetic resonance imaging revealed a previously unrecognized oval hemorrhagic mass lesion at L2-3, which had been inadvertently penetrated during epidural injection. Emergent en bloc resection resolved the patient's neurological symptoms. At histopathologic analysis, the tumor was diagnosed as a spinal paraganglioma.
Discussion: The presented case indicates the importance of a thorough history, physical examination, and imaging assessment before spinal epidural steroid injection.