[Anatomoclinical expressions of polymyositis in the child. 23 cases].

Childhood polymyositis is generally believed to exhibit specific characteristics including involvement of multiple systems, absence of malignancies, severe outcome, cortico-resistance, perforations of the bowel, and inflammatory vasculitis. On the basis of our experience with 23 cases and a review of the literature, we divide childhood polymyositis into five groups: 1) Severe acute dermatomyositis (11 cases) that fits the description above; 2) subacute or chronic polymyositis (4 cases) that resembles the chronic forms seen in adults; 3) infantile polymyositis (3 cases) whose inflammatory origin has not been proved and whose cause may be dystrophic; 4) inclusion polymyositis (2 cases) that are identical with adulthood inclusion myositis; 5) segmentary polymyositis (3 cases). Thus, in children as in adults, polymyositis remains an obscure disease and is a syndrome rather than an entity.