Bilateral insufficiency fracture of the femoral head and neck in a case of oncogenic osteomalacia
ABSTRACT We describe a case of oncogenic osteomalacia in an adult male who presented with low back pain and bilateral hip pain. Extensive investigations had failed to find a cause. A plain pelvic radiograph showed Looser's zones in both femoral necks. MRI confirmed the presence of insufficiency fractures bilaterally in the femoral head and neck. Biochemical investigations confirmed osteomalacia which was unresponsive to treatment with vitamin D and calcium. A persistently low serum phosphate level suggested a diagnosis of hypophosphataemic osteomalacia. The level of fibroblast growth factor-23 was highly raised, indicating the cause as oncogenic osteomalacia. This was confirmed on positron-emission tomography, MRI and excision of a benign fibrous histiocytoma following a rapid recovery. The diagnosis of oncogenic osteomalacia may be delayed due to the non-specific presenting symptoms. Subchondral insufficiency fractures of the femoral head may be missed unless specifically looked for.
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ABSTRACT: Stress fractures, that is fatigue and insufficiency fractures, of the pelvis and lower limb come in many guises. Most doctors are familiar with typical sacral, tibial or metatarsal stress fractures. However, even common and typical presentations can pose diagnostic difficulties especially early after the onset of clinical symptoms. This article reviews the aetiology and pathophysiology of stress fractures and their reflection in the imaging appearances. The role of varying imaging modalities is laid out and typical findings are demonstrated. Emphasis is given to sometimes less well-appreciated fractures, which might be missed and can have devastating consequences for longer term patient outcomes. In particular, atypical femoral shaft fractures and their relationship to bisphosphonates are discussed. Migrating bone marrow oedema syndrome, transient osteoporosis and spontaneous osteonecrosis are reviewed as manifestations of stress fractures. Radiotherapy-related stress fractures are examined in more detail. An overview of typical sites of stress fractures in the pelvis and lower limbs and their particular clinical relevance concludes this review. Teaching Points • Stress fractures indicate bone fatigue or insufficiency or a combination of these. • Radiographic visibility of stress fractures is delayed by 2 to 3 weeks. • MRI is the most sensitive and specific modality for stress fractures. • Stress fractures are often multiple; the underlying cause should be evaluated. • Infratrochanteric lateral femoral fractures suggest an atypical femoral fracture (AFF); endocrinologist referral is advisable.12/2014; 6(1). DOI:10.1007/s13244-014-0371-z
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ABSTRACT: Bilateral insufficiency fractures of the proximal femur often have a pathological basis. Diagnosis of rare causes of insufficiency fractures can be challenging. Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome of mesenchymal tumours which leads to hypophosphataemia and osteomalacia. Suspected pathological fractures should be investigated thoroughly including a fasting serum phosphate level. Further investigations should include serum levels of fibroblast growth factor 23 (FGF23) which is a peptide hormone secreted by mesenchymal tumours. Available imaging modalities include Octreotide scanning which detects somatostatin receptors commonly expressed on mesenchymal tumours. After localisation and resection of the tumour, a full recovery from TIO is achievable.Hip international: the journal of clinical and experimental research on hip pathology and therapy 04/2012; 22(2):227-9. DOI:10.5301/HIP.2012.9235 · 0.34 Impact Factor
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ABSTRACT: PURPOSE: Tumor-induced osteomalacia (TIO) is an endocrine disorder caused by tumors producing excessive fibroblast growth factor-23 (FGF-23). The causative tumors are generally small, slow-growing benign mesenchymal tumors. The only cure of the disease depends on resection of the tumors, which are extremely difficult to localize due to their small sizes and rare locations. Since these tumors are known to express somatostatin receptors, this research was undertaken to evaluate efficacy of [Tc-99m]-HYNIC-octreotide (99mTc-HYNIC-TOC) whole body imaging in this clinical setting METHODS: Images of 99mTc-HYNIC-TOC scans and clinical chart from 183 patients with hypophosphatemia and clinically suspected TIO were retrospectively reviewed. The scan findings were compared to the results of histopathological examinations and clinical follow-ups. RESULTS: Among 183 patients, 72 were confirmed to have TIO while 103 patients were found to have other causes of hypophosphatemia. The possibility of TIO could not be either diagnosed or excluded in the remaining 8 patients. For analytical purposes, these 8 patients who could neither be diagnosed nor excluded as having TIO were regarded as having the disease, bringing the total of TIO patients to 80. The 99mTc-HYNIC-TOC scan identified 69 tumors in 80 patients with TIO, which rendered a sensitivity of 86.3% (69/80). 99mTc-HYNIC-TOC scintigraphy excluded 102 patients without TIO with a specificity of 99.1% (102/103). The overall accuracy of 99mTc-HYNIC-TOC whole body scan in the localization of tumors responsible for osteomalacia is 93.4% (171/183). CONCLUSIONS: Whole body 99mTc-HYNIC-TOC imaging is effective in the localization of occult tumors causing TIO.European journal of radiology 05/2013; DOI:10.1016/j.ejrad.2013.04.006 · 2.65 Impact Factor