|Patient: 65 year old female|
|History: 65 year old female presents with right knee pain. No reported trauma.|
Right knee xrays show a mixed lesion of the tibia. There i a predominantly lytic process from the proximal tibia extending to the mid tibia diaphysis. There is also expansion of the tibia; note that the proximal tibia is wider than the width of the femur.
The Tc99m MDP bone scan demonstrates focal intense radiotracer activity in the proximal tibia to the mid diaphysis which is most prominent in the periphery.
|Diagnosis: PAGET'S DISEASE|
Chronic progressive disease of osteoblasts and osteoclasts resulting in abnormal bone remodeling.
Age: > 40 years (it is unusual to occur in <40 years)
Usually polyostotic and asymmetrical: pelvis > femur > skull > tibia > verterbra > clavicle > humerus > ribs
Active phase = lytic phase = "hot phase"
Aggressive bone resorption: lytic lesions with sharp borders that destroy cortex and advance along the shaft (candle flame, blade of grass)
Usually, lesions start at one end of the bone and slowly extend along the shaft
Bone marrow is replaced by fibrous tissue and disorganized, fragile trabecular
Inactive pahse = quiescent phase = "cold phase"
New bone formation and sclerosis: thickening of the cortex and coarse trabeculations
Mixed pattern = lytic and sclerotic phases coexist
Clinical Findings--Often asymptomatic, painful and warm extremities, bowed long bones, neurologic disorders from nerve or spinal cord compression, enlarged hat size, high output CHF, increased metabolism, elevated serum alkaline phosphotase and urine hydroxyproline
Thickening of cortex and enlargement of bone
Bowing of tibia and femur
Lysis begnins in subarticular location
Candle flame: V-shaped lytic lesion advancing into diaphysis
Osteoporosis circumsmscripta; seen in the osteolytic phase
Cotton wool appearance; mized lytic and sclerotic
Picture frame vertebral body-enlarged vertebral body with peripheral thick trabeculae and inner luceny
Extremely hot lesions in lytic phase
Increased radiotracer uptake typically abuts one joint and extends distally
Cold lesions if inactive
Complications--pathologic fractures, malignant degeneration <1% (osteosarcoma > MFH > chondrosarcoma), giant cell tumors in skull and face, often multiple, secondary OA, bone deformity, high output
Bone scans are useful in determining the extent of the disease
Lesions in the lytic phase are very vascular: dense enhancement by CT
Always evaluate for sarcomatous degeneration
TREATMENT: calcitonin (inhibits bone resorption), Diphosphonate (inhibits demineralization), Mithramycin (cytotoxin)
Primer of Diagnostic Imaging, fourth edition
Essential of Nuclear Medicine, fifth edition
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Case Number: 48180684Last Updated: 11-09-2010 The reader is fully responsible for confirming the accuracy of this content.
The reader is fully responsible for confirming the accuracy of this content.