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METASTATIC BONE TUMOURS.

Dr Raviteja Athkuri

METASTATIC BONE TUMOURS

M.c malignant tumours of skeleton.

Malignant tumours of bone 70% - mets in origin 30%- primary

Almost all tumours metastasize to bone

except 1.BC carinoma of skin,

2.CNS tumours.

Overview of Common Malignant Bone Lesions

M.M mc LYTIC 75% BLASTIC15% MIXED 10%

O.S 2mc LUNG PROSTATE PROSTATE

C.S 3mc BREAST BREAST BREAST

EW.S 4 mc

Primary 30%Secondary 70%

Most Common Causes for Osseous Metastasespopulation lytic blastic

Female Breast 80% Breast 10%

Male Lung 75% Prostate 80%

Young < 20 yrs

NB 80% Hodgkin s 50%

Features of bone mets. 4 th decade.

<5 yr…….NB, 10-20 yrs……EW.,OS, 20-35 yrs……HD.lymphoma.

Principle sign and symptoms..pain,path.#,

Nonspecific ESR, alk.phospatase- blastic s.ca -lytic

Events in development of mets 1.Capable of autonomous survival

after liberation.

2.Pathway of dissemination must be available.

3.Proper environment for growth of implant at new site.

Spread of cancer from one part of the body to another

Path ways 1.direct

2.lymphatic,

3.hematogenous.

Direct pathway. From a soft tissue tumor lying

adjacent to or near the bone.

Example …Carcinoma of the uterus is well known to cause direct extension to the iliac bones.

Mechanical transport of tumor cells by instruments or gloves during surgery,

Less common pathway of direct transplantation is the seeding of tumor along one of the natural pathways in the body,

Lymphatic Dissemination.

Uncommonly play a role in spreading tumor emboli to bone.

Due to absence of lymphatic channels.

Hematogenous Dissemination.

Particularly the veins, is the most common pathway for tumor emboli.

Venous network is a common two-way avenue of metastatic spread of pelvic, abdominal, and thoracic tumors.

arteries are thick walled and often resist tumor penetration.

Three areas most commonly seeded in this manner are the lungs, liver, and axial skeleton.

VERTEBRAL VEIN SYSTEM (BATSON’S VENOUS PLEXUS)

. Batson’s plexus provides a

series of venous passageways by which cancer cells can be directly seeded into the bones, bypassing the liver and lungs

blood flow is sluggish and subject to arrest and even reversal.

Changes in intra-abdominal or intra thoracic pressure may tend to reflux blood flow in the direction of the paravertebral plexus.

Types ------ Lytic lesions,

------Blasic lesion,

------- Mixed lesions.

General radiological features of Metastatic Carcinoma to Bone

Axial skeleton predilection.

Multiple sites

DISTRIBUTION OF SKELETAL METASTASES.

Lytic Destruction

Destruction must occur in the medullary canal before a perceptible alteration of bone density.

Pressure from the proliferating neoplasm on the surrounding trabecular structures and cortices that creates the so-called osteolytic lesion.

At least 30% loss of bone density is necessary before detection

Osteoclasts play little if any role.

majority of metastatic lesions begin within the medullary cavity and secondarily destroy the adjacent cortex.

Metastasis to the cortex occurs uncommonly and is most frequently found in association with carcinoma of the lung, breast, and kidney.

Osteolytic metastases (75%) Cortical and trabecular

destruction,

Lack of periosteal response,

Moth-eaten, permeative destruction,

Small or absent soft tissue mass,

Multiple sites,

Variants (lung, thyroid, kidney);

solitary expansile ( soap bubble

lesion)

Blastic Metastases.

Laying down of new bone, which is non-neoplastic in nature

but is actually a reactive response of the local osteoid tissue to the presence of the tumor.

Osteoblastic metastases (15%) Localized or diffuse

increased bone density,

Poorly defined margins,

Multiple sites,

Mixed metastases (10%)

Combination of blastic and lytic features

Nuclear Imaging (Bone Scans). alterations of as little as 3-5% in the metabolic

activity.

Technetium-99m-methylene dIphosphonate (99mTc-MDP) is the agent of choice because

1. A low radiation dose 2. Convenient half-life for clinical use 3. Monoenergetic 140-keV photon, 4 Ideal for current imaging devices.

Taken up and concentrated in regions of high metabolic activity in bone.

Metastases result in a marked increase in osteoid production and a disproportionate increase in immature woven bone and, therefore, cause a hot spot on bone scans .

MRI appearence

Metastatic deposits contains more water.

Mri appearence Focal lytic lesion…..usual T1-hypo (surroundinf

fat) T2/STIR- hyper

Focal sclerotic ( MB,RB) T1,T2…hypo (bone

forming)

Diffuse heterogenous lesions..NB

T1…inhomog.hypo T2…hyper

Diffuse homogenous lesions T1…homog.hypo T2…hyper

BENIGN CONDITIONS.

positive bone scans Paget’s disease, fibrous dysplasia, fractures, osteomyelitis, osteoid osteoma, osteoblastoma, arthritides, and ischemic necrosis.

Benign Conditions Simulating Osseous Metastatic CancerOsteolytic Osteoblastic

NF MelorheostosisEnchondromatosis OsteopoikilosisPoly ostotic FD Osteopathia striataBrown tumours OsteopetrosisGout PagetsOM SarcoidosisGorhams angiomatosis TS,

Chr.OMSCAMastocytosisFlurosis

Fact ……… nearly 50% pts with spinal metastases present

at autopsy, the lesions were not detectable in premortem tomograms.

Primary organ of involvement

Lytic % Mixed % Blastic %

breast 80 10 10Lung 75 20 5Renal 80 10 10Thyroid 90 10 -----Salivary glands

100

Blow-Out Metastatic Lesions M.c with carcinoma of lung,

thyroid, and kidney.

Although most metastatic lesions are multiple, as many as 10% may be solitary.

Specific charecterstrics of solitory lesion …

bubbly,highly expansile,..renal/thyroid

Solitary plasmacytoma/GCT may also have same appearance.

Differentiating Radiologic Features between Primary and SecondaryLesionsFeature Primary Secondary

Incidence30% 70%

Expansion of bone ++++ +Joint invovement ______________________

________________________

Length of lesion >6 cm 2-4cmPeri osteal response +++ +Solitory lesion +++ +Multiple lesions + +++Soft tissue mass. +++ +

Specific anatomical locations. Spine---- vertebra, Pedicle, Pelvis , Ribs and sternum, Acral ends , Extremities.

Spine

osseous site for metastasis to spine…m .c,

40% of all lesions,

Thoracic and lumbar…….. m.c

Body , pedicle……m.c,

Its very difficult solitary vertebral mets.

Vertebra

earliest and most subtle sign of osteolytic lesion is focal osteoporosis/focal radio lucency of vertebral body.

Bone scan…..incre.uptake

MRI….T1…decr.SI, T2…incr-intemediate. STIR….incre.SI

End plate may shows schmorls nodes due to weakening l/t disruption.

Malignant schmorls….disc herniation into underlying malignancy.

Solitory vertebral collapseMC causesMets.ca ChordomaMyloma (plasma cytoma) HemangiomaEosinophillic granuloma Hydatid cystTraumatic fracture Ewing sarcomaPagets O SInfectionSteroid abuse,cushing disease

G C T

Malig.lymphoma

Pedicle

Any component of post.neural acrch.

Pedicle………..m.c

One eyed pedicle sign/winking owel sign.

Blind vertebra.

At a glance…..

Location …L/T body/pedicles, Signs ……… metabolic bone density dec…moth

eaen/permeative/diffuse incr….localised/ivory

Cortical destruction. Disc space uneffected.

Pathological collapse… decr. Post.V. height., end plate disruption (malig. Schmorl

node)

Pedicle destruction One eyed pedicle

sign, blind vertebra,

DD for pedicle destruction Congenital……agenesis/hypoplasia Neoplasams beningn……ABC OB NFoma OO Malignant……lytic mets myloma.

Ivory vertebra

Osteoblastic metastatic carcinoma,

three most common causes

Prostate

/pagets/H.lymphoma,

Factor Blastic mets Pagets Hodgkin

Age >45 >50 20-40

Incr.density +++ +++ +++

Expansion +++

Anterior scalloping

+++

Acid phasphatase

+++

Alk.phosphatase

++ +++ ++

Solitary ivory vertebraCommon causes Un common causes

OB mets SarcoidosisHD lymphoma ChordomaPaget s MyelomaDegenerative sclerosis OsteosarcomaOM Ewings Idiopathic OO

OBBone island

Pelvis

sacrum and bones of the pelvis … .12% of skeletal mets.

Batson’s venous plexus explains this high incidence,

Blow-out lesions of renal and thyroid origin often affect the bony pelvis,

Skull

10% of met.lesions….. , Lytic mets………….m.c 90%

breast,prostate,thyroid.

Blastic mets…….10% carcinoid

DD….

1.Multiple myloma…

- permeative lytic

-all are in uniform

size.2.mets… lytic with

varying sizes.

Ribs and sternum

28 % of met. bony lesions.

Ribs > sternum,

Any portion of rib, any extent of the rib can involve.

Permeative holes,path.# seen.

Extra pleural sign….m.c by chest wall mets

blow out lesion of renal,thyroid

Acral mets Rarely distal to elbow/knee,

Foot…………m.c, usually missed in

skleletal survey,

breast,lung ,kidney,

Hand……..distal phallanx usually associated with br.ca

Not having periosteal reaction ( dd infe.)

Periosteal reaction Very rare,in the

absence of path.#

Adults………..prostate ,lung ,breast.

Children………neuroblastoma.

Bone invol..preceeds than periosteal invol.

Rarely

Bone Expansion and Soft Tissue Mass can be seen.

COMPLICATIONS

Pain ,pathological #,

>50% cortical bone destruction is needed.

Collapse of vertebra,

Extra dural compression of cord,

Well defined ,moderately built, normal statured,four legged animal…… ………..BLACK COW

Grossly atrophied ,short statured ,horned four legged ……….. ATROPHIED BLACK COW…

Grossly hypertrohied ,gaint ,prominent elongated nose,teeth of four legged aniaml with skin discolouration….. GAINT,HYPERTROPID TRUNCATED COW..

THANK YOU……

Thank you……..