Abstract
A man in his 60s presented with subacute weakness of his lower limbs, numbness, and urinary retention, preceded by fever a few weeks back. Nerve conduction studies showed demyelinating parameters, and magnetic resonance imaging showed long-segment cord T2/STIR hyperintensities and multifocal lesions in the brain. CSF showed albuminocytologic dissociation. Despite immunotherapy with intravenous immunoglobulin (IVIg), symptoms progressed. A PET-CT scan revealed thoracic oesophageal malignancy with lymphatic spread, confirmed on biopsy as an undifferentiated carcinoma. The case was diagnosed as paraneoplastic demyelination involving both the central and peripheral nervous systems. The patient later developed pulmonary thromboembolism. This case highlights simultaneous central and peripheral demyelination as a paraneoplastic manifestation and underscores the need for malignancy screening in demyelinating syndromes unresponsive to standard immunotherapies.