MyPACS.net: Radiology Teaching Files > Case 48180684

Last visited 11-09-2010 PAGET'S
Contributed by: shannon gaffney, Resident, military, Texas, USA.
Patient: 65 year old female
History: 65 year old female presents with right knee pain. No reported trauma.
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Findings:

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
Discussion:

PAGET'S DISEASE:

Chronic progressive disease of osteoblasts and osteoclasts resulting in abnormal bone remodeling.

Unknown etiology.

Age: > 40 years (it is unusual to occur in <40 years)

Usually polyostotic and asymmetrical: pelvis > femur > skull > tibia > verterbra > clavicle > humerus > ribs

Stages:

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

Radiographic Features:

Long Bones:

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

Pelvis:

Thickened trabeculae

Protrusion acetabuli

Skull:

Osteoporosis circumsmscripta; seen in the osteolytic phase

Cotton wool appearance; mized lytic and sclerotic

Diploic widening

Basilar invagination

Spine:

Picture frame vertebral body-enlarged vertebral body with peripheral thick trabeculae and inner luceny

Ivory vertebra

Bone Scan:

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

Pearls:

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)

 

 

 

References:

Stat DX

Primer of Diagnostic Imaging, fourth edition

Essential of Nuclear Medicine, fifth edition

 

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Additional Details:

Case Number: 48180684Last Updated: 11-09-2010
Anatomy: Skeletal System   Pathology: Metabolic
Modality: Conventional Radiograph, Nuc MedAccess Level: Readable by all users

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