Marked improvement of calcinosis in adult dermatomyositis with etidronate therapy

We report a 26-year-old woman with severe calcinosis associated with dermatomyositis. Although calcinosis of the skin or muscles is unusual in adults with dermatomyositis, this patient developed subcutaneous calcinosis with tenderness on the arms, axillary areas, shoulder areas, chest, abdomen, pelvis, and limbs. The calcinosis steadily increased and spread until joint motions were severely limited. Radiographic examination showed extensive soft-tissue calcification with a reticular pattern and severe osteoporosis. The patient was treated with oral etidronate (800 mg/day for 3 months every 6 months) to prevent calcification of the lesions. Three months later, the patient showed a dramatic improvement in symptoms with softening of the calcinosis, reduced pain, and marked increase in joint mobility. Radiographic examination showed marked decreases in the size of the calcified lesions compared to pre-treatment findings, and this effect persisted with a constant progressive efficacy for 3 years. The 3-year course of etidronate therapy also resulted in marked improvement of the severe osteoporosis and the patient was able to return to work and enjoy a normal life. We propose etidronate as a beneficial and effective therapy for calcinosis with osteoporosis.