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