bb5-classifbone.pdf

WHO Classification

of Bone Tumours

Primary neoplasms of the skeleton are rare, amounting to

only 0.2% of the overall human tumour burden. However,

children are frequently affected and the aetiology is

largely unknown.

Significant progress has been made in the histological

and genetic typing of bone tumours. Furthermore,

advances in combined surgical and chemotherapy

havelead to a significant increase in survival rates even

for highly malignant neoplasms, including osteosarcoma

and Ewing sarcoma.

Several bone tumours occur in the setting of inherited

tumour syndromes, but their histology differs little from

the respective sporadic counterparts.

WHO classification of bone tumours

CARTILAGE TUMOURS

Osteochondroma

9210/0*

GIANT CELL TUMOUR

Giant cell tumour

9250/1

Chondroma

9220/0

Malignancy in giant cell tumour

9250/3

Enchondroma

9220/0

Periosteal chondroma

9221/0

Multiple chondromatosis

9220/1

NOTOCHORDAL TUMOURS

Chordoma

9370/3

Chondromyxoid fibroma

9241/0

Chondrosarcoma

9220/3

Central, primary, and secondary

9220/3

VASCULAR TUMOURS

Haemangioma

9120/0

Dedifferentiated

9243/3

Angiosarcoma

9120/3

Mesenchymal

9240/3

Clear cell

9242/3

SMOOTH MUSCLE TUMOURS

Leiomyoma

OSTEOGENIC TUMOURS

Osteoid osteoma

Leiomyosarcoma

8890/0

9191/0

Osteoblastoma

9200/0

Osteosarcoma

9180/3

LIPOGENIC TUMOURS

Lipoma

Conventional

9180/3

8850/0

chondroblastic

9181/3

Liposarcoma

8850/3

fibroblastic

9182/3

osteoblastic

9180/3

Telangiectatic

9183/3

NEURAL TUMOURS

Neurilemmoma

Small cell

9185/3

9560/0

Low grade central

9187/3

Secondary

9180/3

Parosteal

9192/3

MISCELLANEOUS TUMOURS

Adamantinoma

Periosteal

9193/3

9261/3

High grade surface

9194/3

Metastatic malignancy

FIBROGENIC TUMOURS

Desmoplastic fibroma

8823/0

MISCELLANEOUS LESIONS

Aneurysmal bone cyst

Simple cyst

Fibrous dysplasia

Osteofibrous dysplasia

Langerhans cell histiocytosis

Fibrosarcoma

8810/3

FIBROHISTIOCYTIC TUMOURS

Benign fibrous histiocytoma

9751/1

8830/0

Erdheim-Chester disease

Chest wall hamartoma

Malignant fibrous histiocytoma

8830/3

EWING SARCOMA/PRIMITIVE

NEUROECTODERMAL TUMOUR

Ewing sarcoma

JOINT LESIONS

Synovial chondromatosis

9220/0

9260/3

HAEMATOPOIETIC TUMOURS

Plasma cell myeloma

9732/3

___________________________________________________________

* Morphology code of the International Classification of Diseases

for Oncology (ICD-O) {726} and the Systematized Nomenclature

of Medicine (http://snomed.org). Behaviour is coded /0 for benign tumours,

/1 for unspecified, borderline or uncertain behaviour, /2 for in situ carcino-

mas and grade III intraepithelial neoplasia, and /3 for malignant tumours.

226

Chondroblastoma

9230/0

Peripheral

9221/3

8890/3

Malignant lymphoma, NOS

9590/3

WHO classification of tumours of

bone: Introduction

H.D. Dorfman

D. Vanel

B. Czerniak

Y.K. Park

R. Kotz

K.K. Unni

Among the wide array of human neo-

plasms, primary tumours of bone are rel-

atively uncommon. Not only has this con-

tributed to the paucity of meaningful and

useful data about the relative frequency

and incidence rates of the various sub-

types of bone tumours, but it also

explains our rudimentary understanding

of risk factors.

Little information is available concerning

the aetiology and epidemiologic features

of benign bone tumours since most pub-

lished statistical studies have dealt with

bone sarcomas. The benign lesions will

be considered from the epidemiologic

and aetiologic standpoint under the indi-

vidual chapter headings, where they are

known.

malignant fibrous histiocytoma, account-

ing for a marked decline in the frequency

of the former diagnostic category.

lar skeleton has a tendency to decrease

with age. In patients older than fifty,

osteosarcoma of the extremity bones

makes up only 50 % of cases. In this

group, the pelvis and craniofacial bones

each account for about 20 % of the

cases. The incidence rate of extremity

bone involvement for patients older than

50 is approximately one third of that for

persons in the younger age groups.

Chondrosarcomas have age-specific

incidence rates showing a gradual

increase up to age 75. The age adjusted

rates show little difference by sex and

race. More than 50 % of chondrosarco-

mas occur in the long bones of the

extremities. The other major sites of

involvement are the pelvis and ribs. The

latter site and the sternum are high risk

sites for malignant cartilage tumours.

Ewing sarcomahas epidemiological fea-

tures similar to those of osteosarcoma,

but while osteosarcomas tend to occur in

the metaphyseal areas of long bones of

skeletally immature patients, particularly

in the knee region, Ewing sarcoma tends

to arise in the diaphysis. The age-specif-

ic relative frequency and incidence mir-

Age and site distribution

The age-specific frequencies and inci-

dence rates of bone sarcomas as a

group are clearly bimodal. The first well

defined peak occurs during the second

decade of life, while the second occurs

in patients older than sixty. The risk of

development of bone sarcomas during

the second decade of life is close to that

of the older than 60 population, but there

are more cases in the second decade.

The bimodal age-specific incidence rate

pattern of bone sarcomas is clearly dif-

ferent from that of soft tissue sarcomas,

which shows a gradual increase of inci-

dence with age.

Osteosarcoma occurs predominantly in

patients younger than age twenty, and in

this group 80% occur in long bones of

the extremities. In this age group, a small

proportion of cases involve other parts of

the skeleton, such as craniofacial bones,

the spine, and pelvis. The clear predilec-

tion of osteosarcoma for the appendicu-

Incidence

In general, bone sarcomas account for

only 0.2% of all neoplasms for which

data were obtained in one large series

(SEER) {1789}. Comparison of the inci-

dence rate of bone sarcomas with that of

the closely related group of soft tissue

sarcomas indicates that osseous neo-

plasms occur at a rate approximately

one tenth that of their soft tissue counter-

parts {537,946,1304}.

In North America and Europe, the inci-

dence rate for bone sarcomas in males is

approximately 0.8 new cases per 100,000

population and year. Somewhat higher

incidence rates have been observed for

males in Argentina and Brazil (1.5-2) and

Israel (1.4) {1665}. Cancer registry data

with histological stratification indicate that

osteosarcoma is the most common pri-

mary malignant tumour of bone, account-

ing for approximately 35 percent of

cases, followed by chondrosarcoma

(25%), and Ewing sarcoma (16%). In

countries and regions with higher inci-

dence rates, the relative fraction of osteo-

sarcomas appears to be larger.

Chordomas and malignant fibrous histio-

cytoma are much less frequent, constitut-

ing approximately 8 and 5% of bone

tumours, respectively. In recent years, the

diagnosis of fibrosarcoma primary in

bone has largely been replaced by that of

Fig. B.1 Age-specific incidence rates by histological subtype, all races, both sexes, SEER data, 1973-1987. MFH,

malignant fibrous histiocytoma and fibrosarcoma.

227

Relative frequencies of bone sarcomas by histological type, sex, and race: SEER data 1973-1987

es of bone malignancies, other expo-

sures and conditions have been suspect-

ed (e.g. chromium, nickel, cobalt, alu-

minum, titanium, methyl-methacrylate,

and polyethyelene) but not unequivocally

confirmed. Recently attention has been

focused on a small number of reported

cases of bone sarcomas arising in asso-

ciation with implanted metallic hardware

and joint prostheses {788, 879,

1083,1683,2225}. However, the epidemi-

ological evidence for a causitive role is

still limited or inconclusive {6}. Future

molecular epidemiological studies in

patients who have undergone ortho-

paedic implantation of metallic and other

foreign materials may provide clues to

the pathogenetic mechanisms underlying

malignant transformation in bone.

Total

White

Black

Histological type

No.

Osteosarcoma

922

35.1

743

32.6

106

57.9

Chondrosarcoma

677

25.8

615

27.0

19.1

Ewing sarcoma

420

16.0

392

17.3

3.8

Chordoma

221

8.4

200

8.8

2.2

Malignant fibrous histiocytoma 149

5.7

125

5.5

7.1

Angiosarcoma

1.4

1.5

0.5

Unspecified

1.2

1.6

Other

170

6.4

139

6.1

7.8

Total

2627

100.0

2276

100.0

183

100.0

____________

From H. Dorfman & B. Czerniak {537}.

Clinical features

The clinical features of bone tumours are

non-specific, therefore a long period of

time may elapse until the tumour is diag-

nosed. Pain, swelling and general discom-

fort are the cardinal symptoms that lead to

the diagnosis of bone tumours. However,

limited mobility and spontaneous fracture

may also be important features.

ror those of osteosarcoma with the major

peak occurring during the second

decade of life. Although there is a rapid

decrease in incidence after age 20,

cases are seen in all age groups. Unlike

osteosarcoma, Ewing sarcoma is report-

ed to occur almost exclusively in the

white population.

lesions that predispose to malignant

transformation. Others are benign neo-

plasms that can be the source of a malig-

nant neoplastic process. The likelihood of

discovering such associated lesions can

be facilitated by attention to clinicopatho-

logical correlation of all available data

before arriving at a diagnosis. In bone,

the inclusion of radiographic imaging

data in the diagnostic process offers a

unique opportunity to discover clues to

causal relationships that may not be

reflected in histological patterns or in

other laboratory data. This is especially

true when serial radiographs are avail-

able for review.

Paget disease, radiation injury, and some

of the more common benign cartilaginous

dysplasias are the most clearly estab-

lished precancerous conditions. Both

osteosarcoma and malignant fibrous his-

tiocytoma have been linked to pre-exist-

ing condition of bone such as Paget dis-

ease, radiation damage, bone infarction,

fibrous dysplasia, chronic osteomyelitis,

and some genetically determined syn-

dromes {25,132,390,797,867,989,1042,

2263}. The relative rarity of malignant

transformation in fibrous dysplasia,

osteomyelitis, bone cysts, osteogenesis

imperfecta, and bone infarction places

these conditions in a separate category

{540,725,760, 892,1471,2122}.

Precursor lesions

Although the majority of primary bone

malignancies arise do novo, it is increas-

ingly apparent that some develop in

association with recognizable precursors.

Some of these represent non-neoplastic

Precursors of malignancy in bone

High Risk

Ollier disease (Enchondromatosis)

and Maffucci syndrome

Familial retinoblastoma syndrome

Rothmund-Thomson syndrome (RTS)

Fig. B.2 Osteochondroma. Hard, smooth, nodular

swelling of the distal femur, skin and soft tissues are

easily movable and the knee joint is freely mobile.

Moderate Risk

Multiple osteochondromas

Polyostotic Paget disease

Radiation osteitis

Low Risk

Fibrous dysplasia

Bone infarct

Chronic osteomyelitis

Metallic and polyethylene implants

Osteogenesis imperfecta

Giant cell tumour

Osteoblastoma and chondroblastoma

Aetiology

While radiation and chronic inflammatory

states are established, though rare caus-

Fig. B.3 Osteosarcoma, causing swelling in the dis-

tal femur. Soft tissues poorly movable, consistency

ranging from tough to hard, hyperthermia of the skin

and marked veins.

228

additional complaints. Swelling is only

observed if there is an extraosseous part of

the tumour or the bone is expanded by the

tumourous process. In malignant tumours,

swelling develops more rapidly. A descrip-

tion of consistency is important e.g. hard,

coarse, tightly elastic or soft. Metric data

concerning swelling (in centimeters)

should be given; ultrasonic examination

may be helpful to establish objective sizes.

In advanced stages, tumour swelling may

also cause skin changes, including tensed

shining skin with prominent veins, livid

colouring, hyperthermia, as well as stria-

tion of the skin and eventually, ulceration.

The mobility of the skin, subcutis and mus-

culature above the tumour should also be

assessed. The less the mobility, the more

likely is this factor a criterion of malignancy.

fibromas. In cases of malignant bone

tumours, fracture is a rather rare primary

event, as it usually occurs in advanced

stages of osteolytic malignant tumours

and the patient will have experienced

pain and tumour growth prior to it.

General symptoms

These mainly consist of fever, exhaustion

and loss of weight. They are late signs in

malignant tumours, and will be absent in

nearly all cases of benign bone lesions.

Imaging of bone tumours

Diagnosis

Combining both radiological and histo-

logical criteria is most appropriate.

Based on clinical and radiological signs,

one should first diagnose benign lesions

for which a subsequent biopsy may not

be necessary:

> Metaphyseal fibrous defect

> Fibrous dysplasia

> Osteochondroma

> Enchondroma

> Simple bone cyst

> Vertebral haemangioma

Age is useful information: before age of

5, a malignant tumour is often metastatic

neuroblastoma; between 5 and 15 years

old, osteosarcoma or Ewing sarcoma;

and after 40 years, metastasis or myelo-

ma.

The first step is to determine tumour

aggressiveness by conventional radiolo-

gy. Important parameters include tumour

Fig. B.4 Ewing sarcoma of the proximal humerus,

presenting as tightly elastic, tense, ulcerated

lesion with shining skin, on a grey-white back-

ground. Note the marked veins and skin striation.

Limitation of movement

Mobility may be limited in cases of

lesions close to the joint, in tumours such

as osteoblastoma, chrondroblastoma,

giant cell tumours and all types of sarco-

mas. Occasionally it is not the tumour but

reactive synovitis in the joint, especially

in chondroblastoma, that causes limita-

tion of movement and masks the true

diagnosis.

Pain

Pain is the first and most common symp-

tom in nearly all malignant bone tumours

{388,429,1025,1159,1254}. If a sponta-

neous fracture does not occur, the symp-

toms usually commence slowly. Initially

the patient has tearing neuralgia-like

pain, which may also be interpreted as

"rheumatic pain". Although the symptoms

may initially occur intermittently and only

at rest, the pain might subsequently

become more intense, disturb sleep at

night, spread into the adjacent joint and

is frequently misinterpreted as arthritis or

as a post-traumatic phenomenon.

A further intensification of pain is experi-

enced as a persistent and piercing pain.

During disease progression, the pain

becomes excruciating and intolerable,

requiring opiate treatment.

In case of pressure on nerve trunks or

nerve plexuses, the patient may experi-

ence radiating pain. A specific kind of

pain occurs when the tumour is located

in the spine and causes radicular or

spinal compression symptoms with

paralysis.

Pathologic fracture

Fracture is diagnosed early, as it causes

the patient to seek attention immediately.

It may occur with no prior symptoms at

all, as is frequently the case in juvenile

cysts and in some non-ossifying bone

Swelling

The second most important symptom in

bone tumours is swelling, which may fre-

quently be of very long duration, especial-

ly in benign neoplasms, and cause no

Fig. B.5 The choice of the imaging technique.

229

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: