Severe acute inflammatory demyelinating polyradiculoneuropathy with persistent weakness associated with tumor-like nerve root enlargement.

We report a 23-year-old woman with rapid onset of proximal and distal limb weakness and areflexia, associated with tumor-like spinal nerve root enlargement and markedly elevated cerebrospinal fluid protein. Our patient developed the inability to walk within days, without preceding illness. Within two weeks, she had near-complete bilateral wrist and foot drop. Her cranial nerves and respiratory function remained intact. She received intravenous immunoglobulin early on for suspected Guillain-barre syndrome but remained wheelchair-bound until 6 Plasma exchange sessions were completed. After that, she continued to improve with intravenous immunoglobulin dosed every 3-4 weeks. Prominent demyelinating features were found on NCS, with cerebrospinal fluid protein of 415 mg/dL. Comprehensive infectious work-up was negative. Magnetic resonance imaging of lumbosacral and cervical spine showed tumor-like masses mistaken for neurofibromatosis (axial diameter, 7.5-10 mm). Repeated magnetic resonance imaging 6 months later showed persistent nerve root enlargement, despite the patient's improved functional status.