Dermatomiositis juvenil. Interés de la resonancia magnética en el diagnóstico y seguimiento de la enfermedad Juvenile dermatomytositis. Interest of the magnetic resonance in the diagnosis and follow-up of the disease.

Summary Juvenile dermatomyositis (JDM) is the most common pediatric inflammatory myopathy characterized by progressive proximal muscle weakness, heliotrope rash, and erythematous papules and plaques on extensor surfaces. Electromyography and muscular biopsy confirm the clinical diagnosis, but they are invasive techniques. Magnetic resonance findings in this disease may be useful in establishing its diagnosis and follow-up within the clinical context. Often, aggressive and rapid treatment directed can control the acute manifestations and long-range sequelae of JDM, including calcinosis cutis. We report a case of juvenile dermatomyositis with good initial response to low esteroids dose, that we must increased lately. We comment the usefull magnetic resonance findings in our case and in the literature.