Rheumatic diseases such as juvenile dermatomyositis (JDM), juvenile sistemic lupus erythematosus (JSLE) and sistemic sclerosis may have calcium deposits in the subcutaneous and muscle tissues known as calcinosis. Extensive calcium-laden fluid collections referred as "milk of calcium" are rare forms of calcinosis in JDM. We describe a 15-year old patient with overlap syndrome (sclerodermatomyositis and JSLE), whose magnetic resonance imaging (MRI) showed perimusculares fluid collections in the lower limbs. During surgery, we observed the presence of whitish fluid collection suggestive of "milk of calcium".