Isolated AA Amyloidosis of the Radial Nerve.

Amyloidosis affecting peripheral nerve is usually seen in primary amyloidosis.

We are reporting on the case of a 74-year-old man with a 16-month history of progressive left radial nerve paralysis. Perioperative imaging detected an enlarged radial nerve in the middle-distal part of the arm. The patient had an antecedent of amyloid deposits in the lung.

A radial nerve amyloidosis was suspected and confirmed with a biopsy assisted by ultrasonography, resulting in a secondary amyloidosis form.

Isolated radial nerve palsy due to nerve damage by amyloidosis has been reported before, but not in AA or secondary amyloidosis.