Atypical intradural extramedullary spinal schwannoma causing cauda equina syndrome: A case report and literature review

INTRODUCTION: Spinal schwannomas are slow-growing benign tumors that are generally asymptomatic. However, we describe an atypical case in which an intradural extramedullary schwannoma presented as an acute cauda equina syndrome. PRESENTATION OF CASE: This was a 58-year-old woman with a 2-month history of severe low back pain and worsening neurological deficits and a 2-day period of acute onset of lower extremity numbness and urinary incontinence. Physical and neurological examination revealed significant lower extremity weakness, tenderness on palpation of the spine, positive straight leg test bilaterally, decreased sensation below the L4 dermatome, reduced sphincter tone, saddle anesthesia, decreased deep tendon reflexes, and loss of sphincter control, consistent with compression of the cauda equina. Magnetic resonance imaging revealed a large mass of heterogeneous composition at the level of L3 lumbar, intruding into the cauda equina. Wide decompression was successfully performed, and histopathological examination confirmed the diagnosis. With rehabilitation, there was some recovery of lower extremity motor function. DISCUSSION: Spinal schwannomas are rare, accounting for only about 2 % of spinal tumors. Cauda equina syndrome is also rare, with an incidence of 0.08–0.27 % among patients presenting with low back pain. Therefore, it is important for clinicians to have an awareness of the possible association between spinal schwannoma and cauda equina syndrome and to complete a comprehensive assessment of patients with back pain, including magnetic resonance imaging. CONCLUSION: Early recognition and treatment of a spinal schwannoma causing neurological symptoms can improve patient outcomes.