[Isolated loss of function of the flexor pollicis longus muscles in moderate polyneuropathy]

A 60 year old female patient was referred to us with the diagnosis of a traumatic rupture of the flexor pollicis longus tendon. Because of disturbances in sensitivity in the superficial branch of the radial nerve, we carried out a neurological examination. A mild polyneuropathy was found, but there was no evidence against the presence of a trauma-induced rupture of the flexor pollicis longus tendon. In the surgical revision, a rupture could not be detected. However, the musculature of the flexor pollicis longus differed markedly in color and consistency from the other flexors and the histological examination showed atrophy patterns of the muscle fibers which are typical for polyneuropathy of the distal type.