INTRODUCTION
Hydroxyapatite deposition disease, characterized by deposition of calcium crystals around para-articular soft tissues, is often monoarticular and can involve various joints, shoulder being the most common. Other joints like elbow, wrist, hip, knee, ankle, foot, hand and spine can also be affected.1 However, the deposition of calcium salts in the form of an acute calcification around the acromioclavicular joint is a rare condition.2 This condition is usually self-limiting. Unfortunately, some patients remain symptomatic, with no radiographic evidence of improvement.3 This report present a case of acute calcific periarthritis of acromioclavicular joint, presented with acute pain of shoulder, managed conservatively.