[Vertebral localizations of Paget disease].

Paget's disease, often an incidental finding, sometimes presents in the form of pain or signs of complications, such as spinal cord compression, malignant transformation or fissures. The diagnosis is established by laboratory tests, but essentially by radiological findings, based on three basic criteria: cortical thickening, loss of cortico-cancellous differentiation and enlargement of the bone, which deformity is a later sign. The diagnosis can usually be made on plain x-rays, but CT is useful in the case of early, difficult or unusual lesions and complications. CT can reveal mouth-eaten, vacuolar, network, clumped or mixed, fibrillary or ivory images. MRI is a last resort examination. Angioma, metastases and ivory vertebrae are the main differential diagnoses.