A Polyostotic Paget's Disease Involving Lumbar Spine Presenting with Cauda Equina Syndrome: An Unusual Entity.

Introduction: Paget's disease of bone (PDB) is a metabolic bone disease presenting as polyostotic or monostotic lesions of the spine. Although common in the Anglo-Saxon population, it is rare on the Indian subcontinent. Neurological complications though infrequent can be severe in pagetic spine. Case Report: We report a case of a polyostotic variant of PDB involving lumbar spine (L2 vertebrae), iliac bones, and femur presenting as chronic low back pain and neurological deficit, i.e., cauda equina syndrome. On initial workup, a diagnosis of PDB was made and given cauda equina compression with neurological deficit, posterior spinal decompression, and biopsy was performed. The histopathological evaluation confirmed the diagnosis and the patient was treated with bisphosphonates for 6 months, along with serial monitoring of alkaline phosphatase levels. Conclusion: Through this case report, we hope to emphasize that PDB should be considered as a possible cause of neurological symptoms at presentation, especially in elderly patients. Also furthermore, early surgical intervention followed by bisphosphonates therapy can lead to favorable outcomes in such patients.