Dx: Paget disease of bone
Based on the patient’s clinical history and initial imaging studies, which showed characteristic trabecular thickening with bony enlargement of the right femur, we suspected that he had Paget disease of bone. This was confirmed on subsequent whole-body 99mTc-MDP bone scan (Figure 2), which revealed corresponding diffuse increased radiotracer uptake of the right femur. There was no scintigraphic evidence of osseous involvement of the skull, spine, or pelvis.
Epidemiology/incidence. Paget disease, also known as osteitis deformans, is fairly common in the aging population, with a prevalence ranging from 2% to almost 10%.1,2 Although onset before age 40 is rare, the diagnosis should be considered in younger patients, given the high prevalence. There is a slight male predominance, and the disease is more common in the United Kingdom and Western Europe, as well as in countries settled by European immigrants.3
Both genetic and environmental causes are believed to contribute to the pathogenesis of Paget disease. Mutations in the gene encoding sequestosome 1 (SQSTM1) can be seen in the autosomal dominant familial type (25%-50% of these cases), as well as in sporadic cases.4 Environmental influence has also been postulated as a possible cause, with a viral etiology (eg, chronic measles infection) being the most cited.5
Most patients will be asymptomatic
Paget disease can affect any bone in the body, although the skull, spine, pelvis, and long bones of the lower extremity are the most commonly affected sites.2 Most patients with Paget disease are asymptomatic. When symptoms are present, they either result from direct involvement of the bone or are secondary to bone overgrowth and deformity.
Direct involvement manifests as deep, constant bone pain that is worse at night. Symptoms related to bone overgrowth and deformity include spinal stenosis and related neurologic abnormalities, increased skull size, hearing loss (impingement of cranial nerve VIII), pathologic fracture (most commonly of the femur), and deformity such as protrusio acetabuli or femoral or tibial bowing.6 High-output heart failure and abnormalities in calcium and phosphate balance are uncommon but do occur.
Continue to: Degeneration into osteosarcoma...