Autopsy of the body of a person, who died of secondary bacterial pneumonia, revealed pale yellow muscles with numerous calcinosis foci. Microscopy revealed dystrophic changes in the muscles, absence of striations, and reducedglycogen levels. Edema and inflammation are observed in the stroma. The cellular infiltrate is represented by lymphocytes, macrophages, and plasma cells. Sclerotic changes were detected in the heart, lungs, and liver. What is the most likely diagnosis in this case?