[Pneumomediastinum during a dermatomyositis: a rare entity]. / Pneumomédiastin au cours d'une dermatomyosite, une entité rare: à propos d'un cas.

Dermatomyositis is a connective characterized by inflammation of skeletal muscle with cutaneous manifestations. Their etiologies, still unknown, associate environmental and genetic factors. Among lung complications described, interstitial pneumopathies are common complications. Other complications are rarely reported as pneumomediastinum. We report a case of pneumomediastinum with aeric in massive skin dissection occurred in a patient with dermatomyositis. We will discuss the frequency, causes and pathophysiology of the disease according to the literature.