[Monomelic segmental amyotrophy: a Spanish case involving the leg].

A 65-year old male presented with selective amyotrophy of the right lower limb which, after a progressive course of some months, had stabilized 12 years previously. Physical examination showed amyotrophy involving the gastrocnemius and the quadriceps extensor femoris without sensory impairment. EMG suggested motor neuron disease. This case meets Hirayama and Serratrice's criteria for benign chronic monomelic amyotrophy. We support the hypothesis of a casual vascular factor, as proposed by Hirayama.