Neoplastic Bone Diseases

Benign and malignant primary bone tumors are rare, while metastatic disease is a common occurrence. The efficacy of the several currently available imaging modalities in the detection, staging, and follow-up of patients with skeletal neoplasia varies. Evaluation of bone tumors involves a multimodality approach. Standard radiographs play an important role in the diagnosis of both primary and metastatic tumors. Computed tomography (CT) scan and magnetic resonance imaging (MRI) are often complementary and are particularly useful in primary bone tumors. CT scan is especially useful in evaluating the cortex. MRI is superior in evaluating the extent of several primary tumors and detecting bone marrow lesions. The role of bone scintigraphy in the preoperative evaluation of primary tumors is limited. Bone scintigraphy, on the other hand, is an excellent cost-effective screening modality in detecting metastatic disease in patients with skeletal (tumors?) as in the case of extraskeletal malignancies. In breast, lung, and head and neck tumors, bone scans are rarely positive for metastasis in patients with low-stage disease. Positron emission tomography (PET) using F-18 sodium fluoride and FDG, or combined, is more sensitive in detecting metastases. Metaiodobenzylguanidine (MIBG) scintigraphy is valuable in children with neuroblastoma. Conventional bone scan and other radionuclide modalities are valuable in the long-term follow-up of several cancers, and in estimating the prognosis. The therapeutic response of malignant bone disease can particularly be assessed using PET and alternatively, Tl-201 and Tc-99m methoxyisobutylisonitrile (MIBI) in case PET is unavailable.