Case

A 42-year-old woman was referred to our institution with 5 years of progressive proximal and distal weakness, distal paresthesia in lower and upper limbs, severe shocking pain radiating from the neck and lumbar spine to upper and lower limbs, and voice hoarseness. She had previously been diagnosed with multiple plexiform neurofibromas after imaging studies had shown marked nerve hypertrophy. She had no relevant family history. On examination, there was a severe tetraparesis (2/5 distal and 3/5 proximal lower limbs; 4/5 upper limbs), absent reflexes throughout, absent plantar reflexes, stocking and glove sensation loss to all modalities, bilateral foot drop, steppage gait assisted by a walker, a positive Romberg’s sign and no stigmata of neurofibromatosis type 1.

Nerve conduction studies and electromyography showed very slow ulnar motor conduction velocity at 7 m/s, a compound muscle action potential amplitude of 0.2 mV and distal motor latency of 18 ms. Her left R1 blink response was very prolonged at 19.2 ms. Cerebrospinal fluid protein was 0.73 g/L (0.15–0.45), cell count 2/µL …