Abstract
A 44-year-old Japanese woman presented with a five-years duration of erythema on the face, anterior chest, and upper limbs, and a one-month duration of muscular pain of the upper arms and legs. Laboratory data showed that the serum levels of lactate dehydrogenase, aldolase, and myoglobin were high. The titer of antinuclear antibody was 1 : 80, and it showed a speckled pattern. Anti-Mi-2 antibodies were also positive. The deltoid, biceps, and gluteus maximus muscles were bilaterally grade 4 on manual muscle testing, indicating weakness of the proximal muscles. The skin biopsy specimen revealed a keratin plug, vacuolar alteration, colloid bodies, and perivascular infiltration of lymphocytes. This patient was diagnosed as having dermatomyositis from the clinical findings and the pathological features. After admission, 60 mg of prednisolone was administered per day. Rash and muscular symptoms were promptly relieved and laboratory data returned to normal levels. This was a typical case of dermatomyositis with anti-Mi-2 antibodies, which was associated with neither malignant tumor nor interstitial pneumonia. She was successfully treated with oral corticosteroid.
