Diagnostic overshadowing in primary progressive multiple sclerosis with coexisting tethered cord syndrome and long-standing urological dysfunction: a case report and literature review

BACKGROUND: Primary progressive multiple sclerosis (PPMS) may be diagnostically challenging when coexisting structural spinal abnormalities produce overlapping neurological and urinary manifestations. Tethered cord syndrome (TCS) and PPMS can both present with progressive myelopathy and lower urinary tract symptoms, increasing the risk of diagnostic overshadowing. CASE PRESENTATION: A 42-year-old woman with a history of sacrococcygeal meningocele and prior surgical resection presented with a 20-year history of urinary dysfunction and a 2-year history of progressive ascending sensory symptoms and mild paraparesis. Her symptoms had initially been attributed to her structural and surgical history. However, neurological examination, brain and whole-spine MRI, and CSF analysis demonstrated characteristic demyelinating lesions and positive oligoclonal bands. She fulfilled the 2024 McDonald criteria for PPMS. Because ocrelizumab was unavailable locally, rituximab was initiated as an off-label alternative. CONCLUSION: This case highlights the importance of considering a concurrent neuroinflammatory disorder in patients with pre-existing structural spinal pathology and chronic urinary dysfunction. Careful integration of clinical, radiological, and CSF findings is essential to avoid diagnostic delay in complex dual-pathology presentations.