[Familial neoplasms and childhood dermatomyositis].

Familial frequency of malignant neoplasms from 20 children with dermatomyositis was investigated and compared with 225 controls. Eight patients with dermatomyositis (40 per cent) had nine family members with a malignant tumour; this frequency is significantly higher than those found in the controls with juvenile rheumatoid arthritis (P less than 0.01), neoplasms (P less than 0.01), and a variety of diseases (P less than 0.05). This finding and the known association of neoplasm-dermatomyositis might suggest an hereditary predisposing factor, possibly a subtle inmune deficiency, common for tumours and dermatomyositis.