Xray Rounds - A Hole in the Bone
Robbie N Drummond
October 31, 2002
Overview
• Hole found on xray incidental vs presenting symptom
• metastases, benign lesions, malignancies :
• some basic criteria• the impending fracture
• What do we do when a test we order brings up an incidental finding
• Diagnosis made my combination of primary care physician, radiologist, interventional radiologist, histopathologist, oncologist and orthopod
• no definitive pathognomonic findings for specific lesions
• our role to initiate diagnosis and slant treatment
• Is the Lesion infective or neoplastic?
• Is the Lesion benign or malignant?
• Is it a primary or secondary lesion?
• Is the tumour creating or destroying bone?
• Is the cortex of the bone intact, broken or eroded
Five basic presentations of hole in bone
• 1 benign bone tumour
• 2 malignant bone tumour
• 3 metasastases
• 4 non-tumour
• 5 infection
Age
• Osteosarcoma and most malignant tumours are tumours of child hood
• Any invasive lesion < 40 Sarcoma
• any invasive lesion > 40 Metastasis
Location of Common Tumours
Benign Tumours
• Intact cortex
• usually solitary
• enlarges by expansion and pressure... Slowly
• the margin is sharp geographic
• narrow zone of transition
• if part of lesion looks benign whole lesion usually is
• periosteum not affected
Benign Tumour - Chondromyxoid Fibroma
Chondromyxoid Fibroma
• Uncommon benign tumour
• found in proximal tibial metaphyses
• sharply marginated lytic zone of destruction
• sclerotic rim of bone
Malignant Tumours
• Moth -eaten leading to permeative pattern
• wide zone of transition ill-defined lucencies
• small ill-defined lesions
• periosteum involved
• often soft-tissue involvement
OsteoSarcoma
OsteoSarcoma
• Third most common malignancy found in children
• 2,500 new cases a year in USA
• metaphyses usually in femur proximal tibia
• can develop in any bone at any age
• mixed sclerotic and lytic lesion
• periosteal and soft tissue changes
• almost always solitary
X-ray Findings
• Sclerosis visible as a cloudy density
• variable pattern
• permeative moth-eaten pattern
• often periosteal involvement as in onion-skin change of
• Ewings Tumour
Osteomyelitis
Metastases
• 2,000,000 new cancers a year in USA
• half metastasize to bone
• only 8,000 new cases of primary bone cancer a year
• often metastasis is first presentation of cancer
• 50 % of bone gone before found on xray
• hallmark multiple bony lesions (found on bone scan)
Thyroid Metastasis to Femur (note Codman’s triangle)
X-ray Appearance
• Metastasis shows poor margination
• aggressive looking
• variable pattern with soft tissue extension
• periosteal reaction
• can be lytic, blastic or combined
Mets from the Breast
Tumours With Predilection for Spread to Bone
• Prostate 32% blastic goes to pelvis
• Breast 22% lytic prone to fractures long bones
• Kidney 16% lytic aggressive long bones
• Lung lytic can go to hands and feet
• Thyroid usually solitary and lytic
Bone Metastases from breast
Bone Cysts
• Implies hollow often filled with fluid tissue
• circumferential thinned and slightly expanded cortex
• no periosteal involvement
• most are asymptomatic
• 2/3 found after pathological fracture
• children, boys more than girls
• proximal humerus and femur 90%
• calcaneus and ileum in adults
• multiple cysts rare
Xray Appearance
• Arise centrally in bone
• thinning of overlying cortex
• ovoid, symmetrical
• most in metaphysis
• parallel to axis of bone
• geographic and sclerotic margins
Treatment
• Curretage
• insertion of bone chips
• methylprednisolone
• usually never recur
Expanding Aneurysmal Bone Cyst
Bone Cyst With Fallen Fragment
Benign Bone Cyst
The Impending Fracture
• Osteolytic more prone than osteoblastic or mixed• areas of high stress - femur humerus• site of endosteal or periosteal resorption with cortical
thinning• extending more than 50 -75% of original
thickness• interruption in longitudinal or coronal plane > 50%
diameter• lesions > 2.5 cm in femur• persistent pain on weight-bearing despite treatment• can be prevented by change in activity, prophylactic
pinning, radiation therapy
The Impending Fracture
The Impending Fracture
Mirels Risk Score pathological #
• RISK SCORE• VARIABLE 1 2 3• Site upper limb lower limb peritrochanter
• Pain mild moderate severe
• Lesion Blastic mixed lytic
• Size <1/3 1/3 -2/3 >2/3 (diameter)
• fracture likely > 10 unlikely < 7
Conclusions
• We as primary care physicians should be able to initiate the process of diagnosis in lesions found in bone.
• Should be able to differentiate between benign and malignant lesions, primary and secondary lesions and should have some knowledge of non tumourous lesions
• should be able to start to advise the patient on the severity of their disease
• with the help of the pathological fracture scale decide which patient can benefit from prophylactic surgery