Concomitant rheumatoid arthritis and amyotrophic lateral sclerosis. A puzzle illustrated by a new case.

We report a case of amyotrophic lateral sclerosis in a patient with rheumatoid arthritis. Only three similar cases have been reported. Our case illustrates the diagnostic difficulties raised by early amyotrophic lateral sclerosis responsible for localized or unusual manifestations. Occurrence of the two diseases in the same patient is probably due to chance alone.