122 Paget’s Disease

CASE 122


Paget’s Disease


George Nomikos, Hema N. Choudur, Anthony G. Ryan, Peter L. Munk, and Mark Murphey


Clinical Presentation


A 74-year-old man presented with right leg pain.



images

Figure 122A


Radiologic Findings


A plain radiograph of the right femur (Fig. 122A) shows gross deformity and diffuse expansion. Mixed sclerotic and lucent areas are interspersed in the deformed bone, with loss of the normal trabecular pattern.


Diagnosis


Paget’s disease (mixed phase).


Differential Diagnosis



  • Osseous metastases
  • Chronic osteomyelitis

Discussion


Background


Paget’s disease of bone (osteitis deformans) is a common nonhormonal metabolic bone disorder characterized by progressive skeletal deformation due to abnormal bone resorption and remodeling, resulting in osseous overgrowth and weakening. It occurs more frequently in the axial than in the appendicular skeleton. The relative frequency of involvement is, from most involved to least, pelvis, femur, skull, tibia, and vertebrae.


It is most common in Great Britain and in countries colonized by the British, such as the United States, New Zealand, and Australia. It is also common in continental Europe, but it is uncommon in Asia and Africa.


Paget’s disease affects 3 to 4% of the population over 40 years old and 10 to 11% of the population over age 80; there is an overall mild male predominance (1.8:1 male:female ratio). It is uncommon in patients younger than 40 years old.


Etiology


Although the etiology is still uncertain, two entities have been implicated, one, a virus and the other, a genetic predisposition. The viral theory is favored by those authorities pointing to the presence of intranuclear inclusions in the osteoclasts of pagetic bone and the presence of giant osteoclasts. The genetic theory is prevalent, as the condition is known to occur in families.


Pathophysiology


At the outset, there is abnormal resorption of bone due to uncontrolled osteoclastic activity. This is followed by fibrous tissue formation, with disorderly trabeculae being laid down by the osteoblasts; however, the matrix is undermineralized and therefore structurally soft. As the disease progresses, more dense bone is laid down in a haphazard manner.


Clinical Findings


Symptoms of Paget’s disease are variable, and many patients are initially asymptomatic. Common musculoskeletal symptoms include pain, tenderness, warmth (secondary to hypervascularity), osseous enlargement, bowing deformities, and kyphosis. Exacerbation of the pain at rest and at night is typical. Patients may present with a pathological fracture or an increasing bone or soft-tissue mass secondary to malignant transformation (osteosarcomas, chondrosarcomas, malignant fibrous histiocytoma, and giant cell tumors have all been reported in patients with Paget’s disease).


Osseous expansion may lead to nerve compression syndromes, particularly involving the cranial nerves, producing deafness and visual disturbances. Skull deformity and enlargement can lead to increased intracranial pressure and hydrocephalus. Vertebral body enlargement can lead to narrowing of the spinal canal and consequent neurologic deficit, including weakness and incontinence or cranial nerve deficits.


High-output congestive heart failure has been associated with Paget’s disease because of the hypervascularity of the abnormal bone. Aortic stenosis, heart block, and bundle branch block have also been associated with Paget’s disease.


Laboratory values mirror the increased turnover of bone associated with this condition. During the lytic phase, serum and urine levels of hydroxyproline are increased and can be used to assess the degree of bone resorption. Serum alkaline phosphatase is elevated during the mixed and sclerotic phases due to increased bone formation during these phases. Serum calcium and phosphorus are normal.



Figure 122B Multiple fractures are evident on the convex side of the bone, which is bowed with gross cortical thickening.


Stages of Disease



  • Lytic phase Characterized by bone resorption due to excessive osteoclastic activity
  • Mixed phase A phase of simultaneous resorption and bone formation
  • Blastic phase Characterized by erratic bone formation

Complications



Pathology

Feb 14, 2016 | Posted by in MUSCULOSKELETAL IMAGING | Comments Off on 122 Paget’s Disease
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