CLINICAL HISTORY

A 55 year old man was admitted to the rheumatology department owing to inflammatory back pain (occurring at 4 00 am, not aggravated by movement) without sciatica, increasingly severe over two years and associated with asthenia and weight loss (10 kg). No abnormalities were found on physical examination, except for tenderness on palpation of the spinous processes of L5 and S1. There was no significant past medical history. Laboratory tests showed a mild inflammatory picture: erythrocyte sedimentation rate 25 mm/1st h (normal 5–15), C reactive protein 12 mg/l (normal 0–10), fibrinogen 5.1 g/l (normal 2–4). Protein electrophoresis, red and white blood cell count, glucose, renal, and liver function tests were normal. Chemical bone markers (urinary pyridinoline, alkaline phosphatase, osteocalcin, parathormone, 25-hydroxyvitamin D, serum calcium and phosphorus, and urinary calcium and phosphorus) were normal.

RADIOLOGICAL FINDINGS

Standard lumbar spine and pelvic radiographs were normal.

Technetium-99m bone scintigraphy showed no abnormal uptake in the spine or skull but disclosed an increased peripheral uptake.

A skeletal survey showed multiple mixed bone lesions with sclerotic areas surrounding smaller lytic foci. These roughly bilateral, symmetrical lesions involved the metaphyses and diaphyses of some long bones but spared the epiphyses. Bones affected were the femora, tibiae, radii, wrist, and tarsal bones (fig 1⇓).