Clinical Summary

A 67-year-old man present to St. Michaels’s Hospital in 2026 with a one-week history of cauda equina syndrome with urinary retention and paraplegia. His family referred several months’ history of “not being himself”, erythematous rash on chest and face and night sweats without fevers. His medical history included heart failure with preserved ejection fraction, atrial fibrillation, chronic kidney disease (thin basement membrane disease), and polymyalgia rheumatic, for which he had been treated with 15-20 mg of prednisone for the last 3 years. Serum C reactive protein level had been increased and raising over several months. 

He had had an L4-S1 decompression and fusion in 2006, and received multiple epidural steroid injections. MRI and CT imaging showed a dorsal epidural soft tissue thickening at the level of L2-L3, considered suspicious for infection, along with osseous erosions of the posterior elements of L2, resulting in severe spinal canal compression, as well as bilateral foraminal narrowing.

At surgery a large dorsal and right sided epidural mass on the thecal sac was causing severe compression at L2 and L3. The mass was dissected and sent to Pathology and Microbiology. Treatment with antibiotics (Linezolid, Ceftazidime and Cefazolin) was started before surgery and continued with doxycycline.

Discussion points

1. What is the differential diagnosis?
2. What investigations would be appropriate
3. How does the pathological diagnosis affect clinical diagnosis and treatment?