[Extraosseous calcifications in dermatomyositis. A rare differential diagnosis of a benign heterotropic ossification].

Juvenile dermatomyositis is rare but still the most common idiopathic inflammatory myopathy of the childhood. Operative treatment may be indicated, whenever joint motion and patients mobility is limited through the manifestation of calcinosis cutis. Although Vitamin K dependent coagulation pathways have been described, the entire pathophysiological mechanism of its occurrence is currently not clarified. Standard therapy includes the systemic application of steroids and cytotoxins, other options involve aluminum-hydroxid or diltiazem. Only in serious functional obstructions operative resection may be indicated. The case of a 39-year-old female with a 24 year history of dermatomyositis involving most areas of the upper and lower extremities like a coat of mail is presented. Surgical resection of the calcification revealed a good functional recovery of the joint but because of a high recurrency rate the operation is only indicated in special cases.