Misleading clinical aspects of hydroxyapatite deposits: a series of 15 cases.

OBJECTIVE: To study the characteristics of radiographs in diagnosis of hydroxyapatite deposits in sites other than the shoulders and hips. METHODS: We reviewed the records of patients hospitalized during the last 3 years whose final diagnosis was apatite deposits in sites other than the shoulders and hips. RESULTS: Ten women and 5 men were studied. The initial presentation mimicked septic arthritis or periarticular soft tissue abscess in 12 patients, corresponding to calcifications in the fingers (6), toes (2), wrists (2), elbow (1), and ankle (1). One patient presented with a spontaneous coccygeal pain (precoccygeal deposit), one with a pseudotumoral process of the thigh (paradiaphyseal calcification), and one with acute cervical pain and dysphagia (longus coli muscle calcification). Complete clinical healing was observed after an average of 4.9 days; 11 patients used nonsteroidal antiinflammatory drugs (NSAID), 2 used colchicine, one used oral steroids, and one had brief antibiotic therapy and used NSAID. CONCLUSION: Initial clinical aspects of apatite deposits in sites other than the shoulders and hips can often be misleading, especially by mimicking an infectious process. Careful analysis of immediate radiographic films can help to rapidly ascertain the diagnosis and thus avoid useless investigations or treatment.