1503 - Refractory Lumbar Radiculopathy Revealing an Incidental Sacral Canal Myxopapillary Ependymoma: A Case Report

Myxopapillary ependymoma of the S2 canal presenting as refractory lumbar radiculopathy.

Case Description: A 77-year-old female with hypertension, colitis, and chronic bladder incontinence presented with six months of progressively worsening left lumbar radiculopathy radiating into the foot. Pain persisted despite physical therapy and three L5/S1 interlaminar epidural steroid injections, each providing minimal relief. Medication regimen included gabapentin, tramadol, and oxycodone, but she reported worsening weakness and gait instability.

Neurological examination revealed positive straight leg raise on the left, hypersensitivity to touch in L5–S1 dermatomes, and 3/5 weakness in ankle dorsiflexion and great toe extension without cauda equina signs. Electromyography demonstrated active denervation and chronic reinnervation in L5-S1-innervated muscles, discordant with degenerative changes on CT, raising concern for intradural pathology. MRI of the lumbosacral spine with contrast revealed a 2.2 × 0.6 cm well-circumscribed, T2-hyperintense, and homogeneously enhancing intradural lesion at S2, consistent with myxopapillary ependymoma. The patient underwent S2 laminectomy with microsurgical resection, and histopathological analysis confirmed the diagnosis.

Discussions:

This case highlights diagnostic complexity when sacral canal lesions mimic degenerative radiculopathy. Discordance between electromyography and imaging should raise suspicion for intradural pathology, including neoplasms or neuromas. Physiatrists are uniquely positioned to recognize atypical presentations, integrate appropriate diagnostics, and coordinate interdisciplinary management. In this case, the patient engaged in an inpatient rehabilitation postoperatively with an approximate 35% pain reduction and improved function. She continues outpatient physical therapy with ongoing pain management strategies including consideration of neuromodulation approaches such as dorsal root ganglion stimulation.

Conclusions:

Refractory radiculopathy should not be assumed to be degenerative alone. In this patient, diagnostic vigilance led to identification of a sacral myxopapillary ependymoma, highlighting the importance of a systematic approach that integrates clinical, electrodiagnostic, and imaging findings. Early recognition of atypical features and prompt referral for advanced diagnostics are essential to avoid delays in definitive management and preserve neurologic function.