JAOCR at the Viewbox: Paget’s Disease of Bone

A 70-year-old man presented to his primary care physician complaining of worsening pain in the lateral aspect of his left hip. AP views of the pelvis (A) and left hip (B) demonstrate bone expansion, osteosclerosis, as well as cortical and trabecular thickening involving the proximal left femur. An incomplete pathologic fracture involving the lateral cortex of the subtrochanteric left femur is also demonstrated (red arrow in B).

Paget’s disease (osteitis deformans) affects approximately 3% to 4% of the population over age 40 with a second peak of 11% over age 80.¹ Most patients are asymptomatic at diagnosis. It is the second most common bone disease affecting the elderly in the US after osteoporosis.² The exact cause of this disease remains unclear despite first being described in 1877. Proposed etiologies include a chronic viral infection (paramyxovirus); metabolic derangement; neoplasm; and genetic, vascular, and autoimmune diseases.^1,2

Paget’s disease can have a variable appearance on imaging due to the three phases of the disease, which include the lytic, mixed, and osteoblastic phases. Bone destruction predominates in the early stage of the disease followed by attempted repair in the mixed and osteoblastic phases. The distribution of Paget’s disease is often asymmetric and polyostotic. The most common sites of involvement are the spine, pelvis, proximal long bones, and skull.^1,2

Fractures are the most common complication of Paget’s disease. Other complications may include arthropathy, deformity, neurologic entrapment, congestive heart failure, and primary or secondary malignancy.¹ Recognition of the classic imaging features of uncomplicated Paget’s disease is important to avoid an unnecessary bone biopsy.

References

1. Smith SE, Murphey MD, Motamedi K, et al. From the archives of the AFIP: radiologic spectrum of Paget disease of bone and its complications with pathologic correlation. RadioGraphics 2002;22(5):1191-1216.
2. Theodorou DJ, Theodorou SJ, Kakitsubata Y. Imaging of Paget disease of bone and its musculoskeletal complications: review. Am J Roentgenol 2011;196(6_supplement):S64-S75.