Paget's Disease

Charles Hyde, M.D.

B. Leonard Holman, M.D.

March 26, 1983

Case Presentation:

A 55 year-old recent Chinese immigrant was noted to have a sclerotic T11 vertebral body on routine chest x-ray. He was asymptomatic, specifically denying back pain or other bone pain. A bone scintigram was recommended to further evaluate the thoracic vertebral abnormality and to investigate other bone lesions.

Findings:

Tc-99m MDP Bone Scintigraphy:

There is intense uptake of radiotracer throughout one entire T11 vertebral body. Additional note is made of a serpiginous fairly well circumscribed lesion of the right parietal bone.

Radiographs:

The T11 vertebral body is sclerotic, with coarse thickened trabeculae. Overall vertebral size is increased. Disc spaces are normal. The findings are compatible with Paget's disease; however, the appearance may be similar in metastatic prostate cancer, hemangioma, and Hodgkin's disease. There is a large, sharply demarcated low-density lesion in the right parietal region diagnostic for osteoporosis circumscripta (arrows). Both lesions correspond to the scintigraphic abnormalities.

Discussion:

Paget's disease is a common disease of unknown etiology. Nearly any bone can be affected, although involvement by the skull, spine pelvis, femur, tibia, humerus, or scapula is typical. Monostotic or polyostotic patterns are seen, but diffuse involvement is less common.

Involvement before age 40 is unusual; after age 40 Paget's disease can be seen in up to 3% of the population. Men are affected twice as commonly as women.

The lesions (as in this patient) are seldom painful. Some estimate that 90% of lesions remain unrecognized. Involvement of the skull, particularly the skull base, and of the spine may be associated with neurological disturbances. Long bones may develop pathological fractures.

Serum calcium and phosphorus are normal. Alkaline phosphatase is markedly elevated. Urinary excretion of hydroxyproline is elevated.

Histologically, there is intense osteoclastic resorption of normal bone by giant multinucleated cells. Osteoblasts produce exuberant hypervascular new bone. There is distortion and disruption of the organized bony matrix.

Case in Context:

Although intense radionuclide uptake in radiographically affected areas is common, scintigraphic visualization of early Paget's (osteoporosis circumscripta) is uncommon. As the lesion are asymptomatic, imaging is fortuitous. The 99m-Tc-MDP is most intense in the "advancing edge." It has not been convincingly demonstrated whether this is a hypervascular pagetic bone, or the osteoblastic reaction of normal bone in response to the adjacent abnormal and expanding matrix.

Summary:

Early Paget's disease manifesting both osteoporosis circumscripta and destructive lesions by both bone scanning and radiographs.

References:

1) Rauch JM, Resnick D, Goergen TC, et al. Bone scanning in osteolytic Paget's disease. J Nucl Med 1977; 18:699.

2) Frame B, Marel GM. Paget's disease: a review of current knowledge. Radiology 1981; 141:21.

3) Resnick D, Niwayama G. Diagnosis of bone and joint disease. Saunders, 1981, pp. 1721-1754.

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J. Anthony Parker, MD PhD, jap@nucmed.bih.harvard.edu