A case of osteomalacia mimicking ankylosing spondylitis.

A 39-year-old woman presented with symptoms of pain in the lumbar region and lower extremities. Physical findings included restricted movement of the lumbar spine, sacroiliac joint tenderness, positive Schober's test (10-12.5 cm), and bilaterally positive Mennel and Fabere tests. Although these symptoms and findings were suggestive of ankylosing spondylitis, osteomalacia was diagnosed with the appearance of multiple pseudofractures in her pelvic X-ray and laboratory abnormalities. All her symptoms and signs resolved in 6 months with vitamin D and calcium treatment.