Objective: This study was undertaken to describe the musculoskeletal manifestations in a selected population of 26 patients with biopsy-proven osteomalacia (OM) and provide a literature update.
Methods: The 26 patients with biopsy-proven OM were selected from a total number of 79 patients who underwent anterior iliac crest biopsy. The diagnosis of OM was confirmed by the presence of an osteoid volume greater than 10%, osteoid width greater than 15 microm, and delayed mineralization assessed by double-tetracycline labeling.
Results: OM was caused by intestinal malabsorption in 13 patients, whereas six other patients presented with hypophosphatemia of different causes. Five elderly patients presented with hypovitaminosis D, and in two patients the OM was part of renal osteodystrophy. Twenty-three patients presented with bone pain and diffuse demineralization, whereas three other patients had normal or increased bone density. Characteristic pseudofractures were seen in only seven patients. Six of the 23 patients with diffuse demineralization had an "osteoporotic-like pattern" without pseudofractures. Prominent articular manifestations were seen in seven patients, including a rheumatoid arthritis-like picture in three, osteogenic synovitis in three, and ankylosing spondylitis-like in one. Two other patients were referred to us with the diagnosis of possible metastatic bone disease attributable to polyostotic areas of increased radio nuclide uptake caused by pseudofractures. Six patients also had proximal myopathy, two elderly patients were diagnosed as having polymalgia rheumatica, and two young patients were diagnosed as having fibromyalgia. One of the patients who presented with increased bone density was misdiagnosed as possible fluorosis.
Conclusion: OM is usually neglected when compared with other metabolic bone diseases and may present with a variety of clinical and radiographic manifestations mimicking other musculoskeletal disorders.