[Beneficial effect of high-dose etidronate on periarticular calcinosis associated with arterial and periarticular basic calcium phosphate (BCP) crystal deposition disease].

Basic calcium phosphate (BCP) deposition disease is a crystal-induced inflammation syndrome. We report a beneficial effect of high-dose etidronate, one of the bisphosphonates, on periarticular calcinosis in a case of arterial and periarticular BCP crystal deposition disease. A 55-year-old woman was referred to St. Marianna University Hospital because of a 30-year history of recurrent acute periarthritis. The X-ray photographs revealed periarticular calcinosis of the hand and foot, wrist, and knee joints without bony erosions and the calcification of carotid and popliteal arteries. The biopsied specimen from periarticular tissue showed Alizalin-red and von Kossa staining-positive crystals. With the diagnosis of BCP crystal-induced periarthritis, she has been treated with colchicine and probenecid. This regimen was partially effective in terms of a decrease in the frequency of periarthritic attack. Despite the treatment, periarticular calcinosis increased in size and number. She was treated with 800 mg of etidronate 3 months after the etidronate therapy; periarticular calcinosis was diminished although arterial calcification was unchanged. This case suggests that high-dose etidronate might be useful for heterotopic calcification associated with rheumatic diseases.