![]() therapy effects (radiation, chemotherapy, vertebroplasty).primary bone tumors ( osteoblastoma, osteoid osteoma).A score of 7-18 warrants surgical consultation. The spinal instability neoplastic score (SINS) can be used to assess for spinal stability in the presence of vertebral metastases. T1 C+ (Gd): enhancement usually present.Mixed sclerotic and lytic extradural bone lesions The signal intensity of the metastatic deposits will vary according to the degree of mineralization. MRI is sensitive to metastatic disease and is able also to assess for cord compression. Sclerotic lesions appear hyperdense and irregular but are less likely to extend beyond the vertebrae. The mass may breach the cortex and result in compromise of the spinal canal. The more common lytic metastases appear as regions of soft tissue attenuation with irregular margins. The appearance on CT will depend on the degree of mineralization of the metastasis. As metastases have a predilection for involving the posterior vertebral body and pedicle, a missing pedicle (see: absent pedicle sign) is a useful and subtle sign to seek on AP films. Radiographs are useful as an overview but are insensitive to small lytic lesions and struggle to assess for compromise of the canal. It can be difficult, if not impossible, to judge the origin of the tumor from the appearance of the metastatic focus, although some appearances are fairly characteristic. ![]() They can mimic a benign lesion or an aggressive primary bone tumor. Metastatic lesions can have virtually any appearance. Primaries with osteolytic metastases include: Primaries with predominantly osteolytic metastases, that may rarely become osteoblastic (mixed sclerotic and lytic extradural bone lesions) include: Primaries with predominantly osteoblastic metastases (sclerotic extradural bone lesions) include: Having said that some primaries more frequently result in sclerosis than others. New bone formation may also occur after chemotherapy or radiation therapy. Metastases are either osteoblastic or osteolytic, however osteoid formation and mineralization is of limited help in determining the primary tumor as some metastases may secrete osteoblast- and osteoclast-stimulating factors at the same time. The most common primary malignancies to involve the vertebrae include: Lesions may become symptomatic due to bone pain, pathological compression fractures, or extension into the spinal canal with cord compression and ensuing neurological deficits. Vertebral lesions are very frequently asymptomatic in the setting of widespread metastatic disease and are thus often found incidentally when imaging is performed for other reasons (e.g. They are much more frequent in higher age groups (>50 years). Vertebral metastases are already present in 10% of newly-diagnosed cancers.
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