Trigeminal nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy.

An unusual clinical manifestation of nerve hypertrophy in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is described. A patient with a 13-year history of CIDP developed diplopia and proptosis. Imaging of the neuraxis showed marked bilateral trigeminal nerve hypertrophy and lumbosacral nerve root hypertrophy. Biopsy of the right infraorbital nerve revealed inflammatory infiltrates and extensive onion bulb formation, consistent with CIDP.