This 63 year old woman with chronic renal  failure, on haemodialysis, developed painful, hard swellings in her hands and elbows. Radiographs confirmed calcinosis, and material aspirated from a finger was confirmed as hydroxyapatite.  Soft tissue calcification in chronic renal failure may be visceral or non-visceral. Various calcium crystals may be responsible, most commonly calcium phosphates and oxalates.1 Visceral calcification, in heart, lung and muscle, is usually an amorphous compound similar to whitlockite (anhydrous calcium carbonate). Non-visceral calcification in arteries, skin, and periarticular tissues is more commonly hydroxyapatite.2 Deposits may undergo a fibrotic reaction and become encapsulated, appear multiloculated, and spontaneously discharge through the skin.