[Nosological study of 25 cases of chronic monomelic amyotrophy].

The term benign monomelic amyotrophy embraces several types of juvenile amyotrophy of a limb progressing in two stages: first, constitution, then stabilization. Cases reported are in fact heterogeneous and require separation into categories. The cases presented here include: 1) true benign amyotrophy (4 cases); 2) localized forms of chronic sporadic (7 cases) or familial (2 cases) spinal amyotrophy; 3) developmental anomalies and phacomatosis (5 cases); 4) affections of inflammatory origin (4 cases); 5) cases classified as of uncertain but possibly central (1 case) or myosclerotic (1 case) origin, or with the single anomaly of type II fibres (1 case). Obviously that for differential diagnosis to be accurate diagnostic steps differ according to the site of lesions of the predominance upper or lower limbs.