A 61-year-old man presented with an 18-month history of musculoskeletal pain affecting the dorsolumbar spine, ribs and thighs, and a 6-month history of pain and swelling of the left foot. Examination showed rib tenderness, and mild swelling and tenderness of the left foot. The only abnormality detected on initial investigations was a raised alkaline phosphatase of level 266 U/l (normal range 37–170 U/l). Plain radiographs of the lumbar spine and foot were normal, but an isotope bone scan showed extensive hot spots in the left foot and in the ribs bilaterally, which were highly suggestive …