IS Case 116: Paget Disease
Imaging Sciences URMC 2008
Publication Date: 2009-05-20
Patient is a 51-year-old female with left knee pain for one month.
A single AP view of the left knee demonstrates thickened and course trabeculae of the left tibia. Bone scan with whole body and spot images of the abdomen and lower extremities demonstrate abnormal radiotracer uptake in the L3-L4 vertebral bodies and left tibia.
Paget's disease is an exaggerated form of bone remodeling characterized by markedly increased bone resorption followed by new bone formation. The cause of the disease is unknown, but there is a clear genetic link with approximately 40% of patients with Paget's disease having an affected first-degree relative, as well as a large number of families demonstrating a dominant pattern of inheritance. It affects approximately 1-2% of adults older than 55 in the United States.
Patients with Paget's disease have localized areas of accelerated bone remodeling. These areas demonstrate increased numbers of osteoclasts which are hypermultinucleated with up to 100 nuclei per cell, in contrast to normal osteoclasts which contain 3-20 nuclei per cell. This increased number of osteoclasts results in markedly increased bone resorption followed by new bone formation. As new bone formation begins to predominate the bones become enlarged with an abnormal matrix structure due to disordered bone resorption and formation. Over time, the lesions become sclerotic.
The radiographic appearance of Paget’s disease reflects the underlying pathologic changes. Initially there is osteolysis, followed by development of trabecular and cortical thickening and bone enlargement, and finally development of areas of sclerosis. Frequently involved sites include the skull, spine, pelvis, and proximal long bones. Bone scintigraphy typically demonstrates markedly increased uptake of radionuclide in all phases of Paget’s disease. Sarcomatous transformation is seen on images as focal bone destruction extending through the cortex with an associated soft tissue mass. Paget's disease is often asymptomatic, but a minority of patients experience pain, skeletal deformity, and neurologic symptoms, pathologic fractures, or deafness. Sarcomatous transformation may occur in approximately 1% of cases. Symptomatic Paget’s disease may be treated with calcitonin and bisphosphonates.
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- Smith SE, Murphey MD, Motamedi K, Mulligan ME, Resnik CS, Gannon FH. From the archives of the AFIP. Radiologic spectrum of Paget disease of bone and its complications with pathologic correlation. Radiographics. 2002 Sep-Oct;22(5):1191-216. [PMID: 12235348]