MCQ 45 Paget's disease increase the risk of:

A.Osteoma
B.Osteosarcoma
C.Fibrosarcoma
D.All

The correct answer is B.Osteosarcoma

NOTE: Paget's Disease (Osteitis Deformans) is characterized by increased bone turnover and enlargement and thickening of the bone, but the internal architecture is abnormal and the bone is unusually brittle.

Paget's Disease usually begins after the age of 40 years and is more common in whites.The exact cause of this disease is unknown.It has been linked to slow virus infection by Paramyxovirus.

It has the following three stages:

• initial osteolytic stage
• mixed osteoclastic-osteoblastic stage
• Burnt-out osteosclerotic stage

Paget disease is a localized disorder that may be monostotic (affecting only one bone-tibia,ilium,femur,skull,vertebra,humerus) or polyostotic (affecting 2 or more bones-pelvis,spine,skull). Monostotic disease accounts for 10-35% of cases.Paget disease has a predilection for the axial skeleton.

The physical examination findings may be normal in patients with Paget disease. In symptomatic cases, visual inspection may reveal bony deformities, such as an enlarged skull, spinal kyphosis, and bowing of the long bones of the extremities. Bone angulation and deformity may affect joints, with resulting pain and decreased range of motion.

On radiography,the pagetic bone is typically enlarged with thick,coarsened cortices and cancellous bone.

The most useful routine tests are measurement of the serum alkaline phosphatase concentration (which reflects osteoblastic activity and extent of the disease) and 24-hour urinary hydroxy proline (which correlates with bone resorption). Urinary N-telopeptide is a sensitive marker of bone resorption and is helpful in gauging the response to treatment.

Typical bowing of the leg due to Paget's disease involving the right tibia.

Complications in Paget's Disease are:

• Fractures
• Osteoarthritis
• Nerve compression and spinal stenosis
• Bone sarcoma-Osteosarcoma arising in an elderly patient is almost always due to malignant transformation in Paget’s disease.It should always be suspected if a previously diseased bone becomes more painful, swollen and tender. Occasionally it presents as the first evidence of Paget’s disease.
• High-output cardiac failure due to arteriovenous shunts within the marrow
• Hypercalcaemia if the patient is immobalised for long

Calcitonin and Bisphosphonates are used in the treatment of Paget's Disease.

AP view of the pelvis shows classic signs of Paget's disease. On the radiograph of the pelvis, there is evidence of thickening of the femoral neck and diffuse sclerosis of bone. The trabecular bone is more thick than normal bone. The lytic phase of the skull is described as cotton ball appearance and classically known as osteoporosis circumscriptum. Furthermore, the vertebral bodies are also enlarged and occasionally the one is totally sclerotic, thus giving the appearance of an "ivory" vertebral body.