MALIGNANT BONE TUMORS

CONVENTIONAL OSTEOSARCOMA

Definition:

Primary intramedullary high grade malignant

sarcoma in which neoplastic cells produce osteoid.

Epidemiology:

Most common primary non-hematopoietic malignancy of

bone.

Its incidence in USA is 4-5 per milion individuals with

1000-1500 new cases diagnosed annually which

accounts for approximatelly 20% of all primary malignant

cell tumors.

It most frequently occurs in second decade of life with

60% of tumors occuring in patients younger than 25

years.

Although 30% occuring in patients over 40 years of age,

the predisposing condition should always be considered

in older patients (e.g. Paget's disease, of bone, post

radiation sarcoma).

Male to female ratio 3:2.

Osteosarcoma in children 5 years and younger is very

uncommon, and they account for less than 2% of

osteosarcomas in the pediatric population.

Sites of involvement:

Conventional osteosarcoma shows a profound

propensity for involvement of the long bones of the

appendicular skeleton; in particular , the distal femur,

proximal tibia, and proximal humerus.

Within the long bones the tumor is mostly centered in

metaphysis (90%) followed by diaphysis (9%), and

rarely in epiphysis.

Although the long bones remain the most frequent site

of involvement, the non-long bone (i.e, jaws, pelvis,

spine, and skull) involvement tends to increase with

age.

Clinical features:

Classic presentation of conventional osteosarcoma

typically is progressively enlarging, painfull mass.

Deep seated and boring in nature, the pain is frequently

noted months prior to diagnosis, and usually increases

in intensity over time, eventually becoming unbearable.

Skin overlying the tumor may be warm, eyrthematous,

edematous, with prominent engorged veins. Large

tumors may restrict range of motion,decrease

musculoskeletal function,produce joint effusion and, in

advances cases,result in weight loss and cachexia.

A sudden fracture through destructive mass may be

found.

Imaging:

Osteosarcoma has extremely variable radiographic

appearances;

Conventional tumors present as a large,

destructive, poorly defined, mixed lytic and blastic

masses accompanied by cortical destruction and

tumor extension into soft tissue.

Tumor/periosteal interaction may lead to variety of

manifestations secondary to periosteal elevation (e.g.

Codman triangle) and periosteal reactive bone

formation.

Occasionally the tumor may demonstrate

perpendicular or radiating striations called "sunburst".

CT and MRI may be helpfull in delineating the extent

of the tumor preoperatively.

Gross:

Osteosarcoma is often a large (over 5 cm),

metaphyseally centered, fleshy or hard tumor which

may contain cartilage.

It frequently transgresses the cortex and is associated

with a soft tissue mass.

Histopathology:

Presents as highly anaplastic, pleomorphic tumor in

which the tumor cells may be: epithelioid,

plasmacytoid, fusiform, ovoid, small round cells, clear

cells, mono- or multinucleated giant cells, or spindle

cells producing osteoid.

Conventional osteosarcoma can also produce varying

amounts of cartilage and/or fibrous tissue.

Many investigators further subdivide conventional

osteosarcoma in terms of predominant matrix.

This divides conventional sarcoma into three

subtypes:

osteoblastic (50%), chondroblastic (25%), and

fibroblastic (25%) osteosarcoma.

Osteoblastic osteosarcoma:

Bone and/or osteoid are the predominant matrix.

The extremes of matrix production are thin arborising

osteoid to dense, compact osteoid and bone

(sclerotic).

Chondroblastic osteosarcoma:

Chondroid matrix is predominant.

It tends to be high grade hyaline cartilage, which is

intimately associated, and randomly mixed, with

non-chondroid elements.

Fibroblastic osteosarcoma:

A high grade spindle-cell malignancy with

sometimes minimal amount of osseous matrix with

or without cartilage.

In general, the overall histological appearance is

similar to fibrosarcoma or pleomorphic

undifferentiated sarcoma (malignant fibrous

histiocytoma).

Genetics:

Loss of heterozygosity of chromosome arm 3q, 13q,

17p, and 18q most frequent.

Amplification at 1q21-23 and 17p are frequent

findings in conventional osteosarcoma.

Prognosis:

Untreated, conventional osteosarcoma is fatal.

Aggresive local growth and rapid hematogenous

systemic dissemination are bad prognostic features.

Although metastases may affect many sites,

pulmonary metastases are the most frequent site of

clinically significant systemic disease.

In children the treatment of conventional

osteosarcoma is tailored to the location, size and

stage of the tumor.

Eradication of the primary tumor and the elimination

of any matastases is the goal of therapy.

Limb salvage resection is the convention for

appendicular tumors, and surgical excision in

combination with radiation is employed for tumors

that are not resectable entirely with negative

margins.

Adjuvant chemotherapy is usually employed in the

preoperative setting and continued after surgical

resection.

Survival is directly related to response to

pre-operative therapy. In those patients whose

tumors have >90% tumor necrosis, long-term

survival is generally 80-90%.

In patients with < 90% response to therapy the

survival is poor, usually <15%.

TELANGIECTATIC OSTEOSARCOMA

Definition:

•

Malignant bone forming tumor characterized by large

spaces filled with blood with or without septa.

Epidemiology:

•

Rare subtype, accounting for less than 4% of all cases of

osteosarcoma.

•

It most frequently occurs in the second decade of life but

was described in younger patients.

•

Male to female ratio 1.5:1.

Sites of involvement:

•

Most tumors involve metaphyseal region of long tubular

bones.

•

Distal femoral metaphysis is the single most common

anatomic site, followed by the upper tibia and proximal

humerus or proximal femur.

Clinical findings:

•

Similar to conventional osteosarcoma.

•

Characteristic clinical finding of this tumor is pathological

fracture (1/4 of the cases),because of massive bone

destruction.

Imaging:

•

Purely lytic, large bone destruction without distinct

surrounding bony sclerosis.

•

Tumor commonly show extension into soft tissue.

•

Most lesions are located in metaphysis, and ususally

extend into the epiphysis.

•

Tumor often expand the cortex of bone and distrupt the

cortex.

•

Periosteal reaction including Codman's triangle and onion

skin are frequent.

•

MRI, a T1-weghted image shows heterogenous low signal

intensity, and T2-weighted image shows high signal

intensity with several cystic foci and fluid-fluid level with an

extraskeletal extension of the tumor, similar to aneurysmal

bone cyst.

Gross:

•

Tumors show dominant cystic architecture in the medullary

space.

•

Cystic portion of the tumor is filled incompletely with blood

clot which is described as "a bag of blood".

•

There is no sclerotic tumor bone formation.

Histopathology:

•

Tumor contains blood-filled or empty spaces separated by

thin septa simulating aneurysmal bone cyst.

•

A few of the tumors are more solid and have smaller cystic

spaces.

•

Higher power view shows the cystic spaces lined by

benign-looking giant cells without endothelial cells.

•

The septa are cellular, containg atypical mononuclear tumor

cells.

•

Tumor cells are hyperchromatic and pleomorphic with high

mitotic activity including atypical mitoses.

•

Amount of osteoid varies, but usually fine, and lace like

osteoid is observed in minimal amount.

•

Cellular septae contain many benign looking

multinucleated giant cells, which may lead to a mistaken

diagnosis of benign or even malignant giant cell tumor.

Genetics:

•

Mutations in TP53 and RAS genes.

Prognosis:

•

Similar to conventional osteosarcoma.

•

Sensitive to chemotherapy.

SMALL CELL OSTEOSARCOMA

Definition:

•

Osteosarcoma composed of small cells with variable degree

of steoid production.

Epidemiology:

•

Small cell osteosarcoma comprises 1.5% of

osteosarcomas.

•

Patients range from 5 to 80 y/o, although most patients are

in the second decade.

•

There is slight predilection for females.

Sites of involvement:

•

Metaphysis of long bones. Rarely multiple sites are involved.

Clinical findings:

•

Pain and swelling of involved site.

Imaging:

•

Aggressive process with destruction of the cortex.

•

There is always a lytic component, usually admixed with

radiodense areas.

•

Mineralized tissue is seen, either intramedullary and/or in

soft tissue tumor extension.

Histopathology:

•

Small cell osteosarcoma is composed of small cells

associated with osteoid production.

•

Nuclear diameter of round cells can range in size from very

small to medium; the smaller one are comparable to those

of Ewing sarcoma or lymphoma.

•

The cells have scanty amounts of cytoplasm. Nuclei are

round to oval and the chromatin may be fine to coarse.

•

Mitoses range from 3 to 5 /HPF.

•

In the less frequent spindle cell type, nuclei are short, oval

to spindle, have a granular chromatin, inconspicuous

nucleoli and scanty amounts of cytoplasm.

•

Lace-like osteoid is always present.

•

Biopsy from small cell osteosarcoma may be problematic,

especially from the peripheral surface of the tumor, because

may not always show osteoid and may resemble Ewing

sarcoma.

•

In this cases cytogenetic study for t(11,22) is the best

diagnostic tool, which is negative in small cell

osteosarcoma.

Immunohistochemistry:

•

Positive for CD99, vimentin, osteocalcin, osteonectin.

Genetics:

•

Negative for t(11,22).

Prognosis:

•

Poor.

LOW GRADE CENTRAL OSTEOSARCOMA

Definition:

•

Low grade osteosarcoma that arises from the medullary

cavity of bone.

Epidemiology:

•

Accounts for less than 1% of primary bone tumors and only

1-2% of all osteosarcomas.

•

Males and females are equally affected.

•

The peak incidence is in 2nd-3rd decades of life.

Sites of invovement:

•

Approximately 80% of low grade central osteosarcoma are

located in the long bones with predilection for the distal

femur and proximal tibia.

•

Flat bones are uncommonly affected.

Clinical features:

•

Pain and swelling are usual features.

•

The duration of pain may be many months or even several

years.

Imaging:

•

Large metaphyseal or diaphyseal intramedullary tumors.

•

It is not uncommon to see extension into the end of the

bone when the epiphyseal plate is closed.

•

Majority of tumors are poorly marginated, up to 1/3 may

show intermediate or well defined margins suggestive of

indolent or benign lesion.

•

Trabeculation and sclerosis are common findings that

reflects indolent nature of this tumor.

•

Cortical destruction is the most convincing radigraphic

feature to support malignant nature of the tumor.

•

The majority of low grade central osteosarcomas will show

some degree of cortical destruction with or without soft

tissue extension.

Gross:

•

Cut surface of a low grade central osteosarcoma shows a

grey-white tumor with a firm and gritty texture arising from

within the medullary cavity.

Histopathology:

•

Low grade osteosarcoma is composed of a hypo- to

moderately cellular fibroblastic stroma with variable amounts

of osteoid production.

•

The collagen producing spindle cells are arranged in

interlacing bundles thet permeate surrounding pre-existing

bony trabeculae and bone marrow similar to that of

desmoplastic fibroma.

•

Tumor cell show some degree of cytological atypia.

•

Nuclear enlargement and hyperchromasia are evident.

•

Occasional mitotic figures are identified.

•

Variable patterns of bone production are seen.

•

Some tumors contain irregular anastomosing, branching,

and curved trabeculae simulating the appearance of woven

bone in fibrous dysplasia ( no atypia seen in spindle cells of

fibrous dysplasia).

•

Small scattered foci of atypical cartilage are occasionally

seen.

•

In addition, benign multinucleated giant cells have been

reported in up to 36% of cases.

Genetics:

•

Recurrent gains in minimal common regions at 12q13-14,

12p, and 6p21.

Prognosis:

•

Low grade central osteosarcoma behaves in a much more

indolent fashion conventional osteosarcoma.

•

High incidence of local recurrence after inadequate excision.

•

Recurrence may exhibit higher grade or differentiation with

the potential for metastases.

PAROSTEAL OSTEOSARCOMA

Definition:

•

Parosteal osteosarcoma is a low grade osteosarcoma which

arises on the surface of bone.

Epidemiology:

•

Although rare , parosteal osteosarcoma is the most common

type osteosarcoma of the surface of bone.

•

It accounts for about 4% of osteosarcomas.

•

There is a slight female predominnce.

•

Most of the patients are young adults, about 1/3 occurs in

3rd decade of life.

Sites of involvement:

•

70% of cases involve the surface of the distal posterior femur.

•

The proximal tibia and proximal humerus are also common.

Clinical findings:

•

Painles swelling; inability to flex the knee may be the initial

symptom.

•

Some patients may complain of a painful swelling.

Imaging:

•

Heavily mineralized mass attached to the cortex with broad

base.

•

Tumor has tendency to wrap around the involved bone.

•

CT and MRI are useful in evaluating the extent of medullary

involvement.

Gross:

•

Parosteal osteosarcoma presents as a hard lobulated mass

attached to the undrelying cortex.

•

Nodules of cartilage may be present.

•

Occasionally, the cartilage will be incomplete cap-like,

covering the surface and thus suggesting a diagnosis of

osteochondroma.

Histopathology:

•

Parosteal osteosarcoma consist of well formed bony

trabeculae in spindle cell stroma.

•

The spindle cells show minimal atypia, mitoses can be found

with difficulty, atypical forms are not present.

•

The bony trabeculae are arranged in a parallel manner and

simulate normal bone.

•

The trabeculae may or may not show osteoblastic rimming.

•

About 50% of the tumors will show cartilagenous

differentiation. This may be in the form of hypercellular

nodules of cartilage within the tumor or as a cap on the

surface.

•

When cartilage cap is present may be mildly hypercelllular,

and the cells may show mild atypia and lack columnar

arrangemet seen in osteochondroma.

•

Unlike fatty and hematopietic marrow, as seen in

osteochondromas, there is spindle cell proliferattion

between bony trabeculae.

•

About 15% will show high grade spindle cell sarcoma

(dedifferentiation).

Prognosis:

•

Excellent with 91% overall survival at 5 years.

PERIOSTEAL OSTEOSARCOMA

Definition:

•

Periosteal osteosarcoma is intermediate grade chondroblastic

osteosarcoma arising on the surface of the bone.

Epidemiology:

•

Accounts for less than 2% of all the osteosarcomas.

•

Of the surface osteosarcomas, it is more common than

surface high grade osteosarcoma, but about 1/3 as common

as parosteal osteosarcoma.

•

The peak incidence is the 2nd and 3rd decades of life.

•

There is a slight male predominance.

Sites of involvement:

•

Diaphysis or diaphyseal-metaphyseal area of long bones, with

the tibia and femmur most commonly affected.

Clinical features:

•

Painless mass or limb swelling is the most common initial

finding with pain and tenderness later developing in the

affected area.

Imaging:

•

Arising on the surface of a bone, displays nonhomogenous,

calcified spiculations that are disposed perpendicular to the

cortex and give overall sunburst appearance.

•

The lesion decreases in density from the cortical base to the

surface, where the tumor has a relatively well demarcated

margin.

•

Commonly, the cortex appears thickened as a result of the

production of ossified matrix.

•

A codman's triangle is commonly present.

•

CT and MRI important in the evaluation of tumor size,

integrity of the cortex, and soft tissue extension.

Gross:

•

Tumor arises from the bone surface and may involve part of

the bone or the entire circumference.

Histopathology:

•

Periosteal osteosarcoma has the appearance of a moderately

differentiated chondroblastic osteosarcoma.

•

Ossified mass is generally found arising from the cortex, and

is made up of relatively mature bone.

•

Cartilagenous component predominates, but elements of

intermediate grade osteosarcoma are invariably present.

•

Cartilagenous component may show varying degrees of

cytological atypia and matrix may be myxoid.

•

Periphery is most of the time not calcified and made of

fascicles of spindle cells.

Prognosis:

•

Better prognosis than conventional osteosarcoma, but still

have tendency to recur and metastasize.

•

Medullary involvement of the bone may have poorer prognosis.

•

About 70% recurrence rate after excision.

•

Rate of metastasis has been reported to be about 15%.

HIGH GRADE SURFACE OSTEOSARCOMA

Definition:

•

High grade bone forming malignancy which arises from the

surface of the bone.

Epidemiology:

•

Less than 1% of all osteosarcomas.

•

Peak incidence is in 2nd decade of life.

•

There is slight male predilection.

Sites of involvement:

•

Femur is most commonly affected followed by frequency by

the humerus and tibia.

Clinical features:

•

Patients commonly present with the mass or pain in the area

of the tumor.

Imaging:

•

Surface mass, partially mineralised, extending to soft tissue.

•

The underlying cortex is commonly partially destroyed, and

periosteal new bone is commonly present at the periphery of

the tumor.

•

Cross sectional imaging may show minimal medullary

involvement, but the tumor is most comonly relateively well

circumscribed at its soft tissue margin.

Gross:

•

Tumor is situated on the surface of the bone and commonly

erodes the underlying cortical bone.

Histopathology:

•

Show similar morphology to conventional osteosarcoma.

•

Regions of predominantly osteoblastic, chondroblastic or

fibroblastic differentiation may predominate.

•

However, all tumors will show high grade cytological atypia

and lace-like osteoid as seen in conventional osteosarcoma.

Prognosis:

•

As in conventional osteosarcoma, prognostic feature is

response to chemotherapy.

SECONDARY OSTEOSARCOMA

Definition:

•

Bone forming sarcomas occuring in bones affected by

preexisting abnormalities the most common

being postradiation therapy chnges, Paget disease, and rarely

various other disorders.

POSTRADIATION OSTEOSARCOMA

Epidemiology:

•

Consitute 3.4-5.5% of all osteosarcomas and 50-60% of

radiation-induced sarcomas.

•

It is estimated thet the risk of developing osteosarcomain

irradiated bone is 0.03-0.8%.

•

Children treated with high-dose radiotherapy and

chemotherapy are at greatest risk.

•

The prevalence of post-radiation osteosarcomas is increasing

as children survive treatment of their malignant disease.

Sites of involvement:

•

Any irradited bone, but the most common locations are the

pelvis and the shoulder region.

Clinical findings:

•

H/O of previous radiation therapy and tumor developing in the

path of radiation beam.

•

A symptom free latent period may be long (median of 11

years), and inversely related to the radiation dosage.

•

Radiation doses are usually greter than 20 Gy.

•

From experience I've seen few osteosarcomas in patients with

h/o of synovial sarcoma radiation therapy in young children.

Imaging:

•

Tumors are densly sclerotic or lytic lesions with a soft tissue mass.

•

Radiation osteitis is present in about 50% of cases (trabecular

coarsening and lytic areas in cortex).

Histopathology:

•

High grade osteosarcoma predominate (see conventional

osteosarcma).

Prognosis:

•

5-year survival rate is of 68.2% for patients with extremity

lesions, 27.3% for patients with axial lesions.

PAGET OSTEOSARCOMA

•

Paget disease is estimated to be 0.7-0.955, and

osteosarcomas represent 50-60% of Paget sarcomas.

•

In most series, Paget osteosarcoma is more common in man

(M:F 2:1), with an overall median age of 64 years.

•

It is osteosarcoma of older patients, not found in pediatric

population.

OSTEOSARCOMA ASSOCIATED WITH FIBROUS DYSPLASIA

•

Most commonly associated with Albright syndrome (also

called McCune-Allbright syndrome and polyostotic fibrous

dysplasia = bone polyostotic fibrous dysplasia+ skin

pigmentation and precosious puberty (other endocrine

abnormalities)

EWING SARCOMA/ PRIMITIVE NEUROECTODERMAL TUMOR (PNET)

Definition:

•

Ewing sarcoma/PNET are defined as small round cell sarcoma

(belong to group of pediatric small blue cell tumors) that show

varying degrees of neuroectodermal differentiation.

•

Ewing sarcoma is used term for those tumors which lack

neuroectodermal differentiation, and PNET has been described

for tumors with neuroectodermal differentiation.

Epidemiology:

•

Ewing sarcoma accounts for 6-8% of primary bone tumors.

•

It is the second most common sarcoma in bone in children.

•

Male:female ratio 1.4: 1.

•

Nearly 80% are younger than 20 y/o, and the peak incidence is

during the second decade of life.

Sites of involvement:

•

Arise in the diaphysis or metaphyseal-diaphyseal portion of

long bones.

•

The pelvis and ribs are also common locations.

Clinical features:

•

Pain and a mass in the involved area are the most common

clinical symptoms.

•

Fever, anemia, leukocytosis and increased sedimentation rate

are often seen.

Imaging:

•

Ill defined osteolytic lesion involving diaphysis of long bone or

flat bone is the most common feature.

•

Permeative or motheaten bone destruction often associated

with "onion-skin" like multilayered periosteal reaction is

characteristic.

•

The cortex overlying the ti=umor is irregulary thinned and

thickened.

•

A large ill-defined soft tissue mass is frequently seen.

•

Expansile bone destruction with soap-bubble appearance might

be seen.

Gross:

•

The tumor in bone and soft tissue is tan-grey and often necrotic

and hemorrhagic.

Histopathology:

•

Most cases are composed of of uniform small round cells with

round nuclei containing fine chromatin, scanty clear or

eosinophilic cytoplasm, and indistinct cytoplasmic

membranes, whereas in others, the tumor cells are larger, have

prominent nucleoli, and irregular contours.

•

The cytoplasm of the tumors frequently contains PAS positive

glycogen ( diastase sensitive).

•

In some cases Homer-Wright rosettes are present.

•

Necrosis is common with viable cells frequently perivascular in

distribution.

Immunophemotype:

•

Positive: Fli-1, CD99, vimentin, neuron specific enolase (NSE),

PAS+ diastase sensitive.

•

Negative: S100, CD45, muscular and vascular markers

Genetics:

•

t(11,22) (q24;q12) - 85%

•

t(21;22) (q22;q12) - 10-15%

•

t(7;22), t(17;22), t(2;22) - 1%

Prognosis:

•

Has improved with adjuvant therapy.

•

Important prognostic features include the stage, anatomic

location and the size of the tumor.

•

Tumors that are metastatic at the time of the diagnosis, arise

in the pelvis, and when they are large tend to do poorly.

LYMPHOMA OF BONE

Definition:

•

Malignant lymphoma is a neoplasm composed of malignant

lymphoid cells, producing a intra-medullary tumor mass.

Epidemiology:

•

Malignant lymphoma involving bone is not common, accounting

for approximately 7% of all bone malignancies.

•

Lymphomas involving bone account for about 5% of extranodal

lymphoma.

•

Patients may be of any age group but there is tendency to

involve adults, especially older patients, although there were

cases of young childrens causing difficult diagnostic

differentiation from Ewing sarcoma.

Sites of involvement:

•

Affects portion of bone with persistent bone marrow.

•

Femur is the most commonly involved single site.

•

It is extremely unusual to see malignant lymphoma involving

the small bones of the hand and feet.

•

Clinical features:

•

Majority of patients present with bone pain.

•

Some patients may present with palpable mass.

•

Patients with primary lymphoma of bone rarely present with

systemic symptoms like fever or night sweats.

•

Lymphoma involving bone may be separated into four groups:

1) an single skeletal site, with or without regional lymph node

involvement;

2) multiple bones are involved, but there is no visceral or lymph

node involvement;

3) patients present with a bone tumor but work up shows

involvement of other visceral sites or multiple lymph node

sites;

4)patient has a known lymphoma and the bone biopsy is done to

r/o involvement of bone;

Groups 1 and 2 are considered primary lymphoma of bone.

Imaging:

•

In the long bones, diaphysis tends to be more involved.

•

Tumor tends to involve a large portion of bone; it is not unusual

to see destruction of more than half of the bone.

•

The process is poorly demarcated with a wide area of transition

from normal bone.

•

There may be variable sclerosis; rarely, the tumor is very

sclerotic or entirely lytic.

•

Most of the time there is mixture of sclerotic and lytic areas.

•

Cortex is frequently destroyed and there is large soft tissue

mass.

•

A purely sclerotic lesion may be mistaken for Paget's disease.

•

If the cortex is not involved, the marrow destruction may not be

obvious on plain roentgenograms.

•

Radionuclide bone scan is almost always positive.

Gross:

•

Llarge portion of bone is involved, with cortical destruction.

•

The lesion has the soft fish-flesh appearance of lymphoma.

Histopathology:

•

Majority of lymphomas invoving bones show diffuse growth

pattern.

•

Follicular small cell cleaved cell lymphoma is common in bone

marrow, although in most of the cases does not present as

destructive bone tumor.

•

Similarly, chronic lymphocytic leukemia rarely present as

tumefactive process.

•

Consquently, most of the bone lymphomas are diffuse large

cell type.

•

It has characteristic permeative growth pattern.

•

Bony trabeculae may appear normal or may appear thickened

or irregular, even Pagetoid. 92% of primary non-Hodgkin

lymphoma of bone was found to be of the large B cell type and

only 3% diffuse follicle centre cell, #% anaplastic large cell and

2% immunocytoma.

•

One problem with the diagnosis of lymphoma in bone is that

the calls tend to get crushed.

•

If a bone biopsy shows such a crush artifact, a diagnosis of

malignant lymphoma should be suspected.

•

Hodgkin lymphoma may involve the skeleton as a

manifestation of a wide spread disease and produce a tumor

mass but primary manifestations are rare.

Prognosis:

•

Prognosis of lymphoma is assocuiated with cell type and

stage of disease.

•

Patients older than 60 y/o have a worse overall survival and a

worse progression-free period.

•

Patients with immunoblastic subtype has a worse survival

than the centroblastic mono/polymorphic subtype or the

centroblastic multilobulated subtype.

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CHONDROSARCOMA

Definition:

•

Chondrosarcoma (CHS) is a malignant tumour with hyaline cartilage differentiation.

•

Myxoid changes, calcification or ossification may be present.

Epidemiology:

•

Primary CHS accounts for approximately 20% of malignant

bone tumours.

•

It is the third most common primary malignancy of bone after

myeloma and osteosarcoma.

•

Tumour of adulthood and old age.

•

The majority of patients are older than 50 years. The peak

incidence is in the fifth to seventh decades of life.

•

There is a slight preference for male.

•

Very rare in younger patients, although if in younger patients

usually present as high grade.

Sites of involvement:

•

Most common skeletal sites are the bones of the pelvis (the

ilium is the most frequently involved bone) followed by the

proximal femur, proximal humerus, distal femur and ribs.

•

The small bones of the hands and feet are rarely involved by

primary CHS (1% of all CHS).

•

Extremely rare in the spine and craniofacial bones.

Clinical findings:

•

Local swelling and pain, alone or in combination, are significant

presenting symptoms.

•

The symptoms are usually of long duration (several months or

years).

Imaging:

•

In the long bones primary CHS occur in the metaphysis or

diaphysis were the produce fusiform expansion with cortical

thickening of the bone.

•

CHS produce fusiform expansion with cortical thickening of the

bone.

•

CHS present as an area of radiolucency with variably

distributed punctate or ring-like opacities(mineralization).

•

Cortical erosion or destruction is usually present.

•

Cortex is often thickened but periosteal reaction is scant or

absent.

•

MRI can be helpful in delineating the extent of the tumour and

establishing the presence of soft tissue extension.

•

CT scans aid in demonstrating matrix calcification.

Gross:

•

Cut surfaces of CHS tend to have a translucent, blue-grey or

white color corresponding to the presence of hyaline cartilage.

•

Lobular growth pattern is a consistent finding.

•

There may be zones containing myxoid or mucoid material and

cystic areas.

•

Erosion and destruction of the cortex with extension into soft

tissue may be present expecially in CHS of the flat bones

pelvis, scapula and sternum).

Histopathology:

•

Low magnification CHS shows abundant blue-grey cartilage

matrix production.

•

Lobules of cartilage varying in size and shape are present.

•

Lobules may be separated by fibrous bands or permeate bony3

trabeculae.

•

CHS are hypercellular when compared to an enchondroma.

•

Chondrocytes are atypical varying in size and shape and

contain enlarged, hyperchromatic nuclei. Extent of atypia is

usually mild to moderate.

•

Binucleation is frequently seen.

•

Permeation of cortical and/or medullary bone is an important

characteristic of CHS that can be used to separate it from

enchondroma.

•

Myxoid changes or chondroid matrix liquefaction is a common

feature of chondrosarcomas.

•

Necrosis and mitoses can be seen in chondrosarcoma,

particularly in high grade lesions.

•

CHS in a small bone of the hand and foot are different.

Increased cellularity, binucleated cells, hyperchromasia and

myxoid change may all be present in enchondroma in this

location.

•

The most significant histological feature of CHS involving the

small bones is permeationthrough the cortex into soft tissue

and a permeative pattern in the cancellous bone.

•

Chondrosarcomas are graded on a scale of 1-3

•

Grade 1: Tumours are moderately cellular and contain

hyperchromatic plumpnuclei of uniform size. Occasionally

binucleated cells are present. The cytology is very similar to

enchondroma.

•

Grade 2: Tumours are more cellular and contain a greater

degree of nuclear atypia, hyperchromasia and nuclear size.

•

Grade 3 lesions are more cellular and pleomorphic and atypical

than grade 2.

Prognosis:

•

Five-year survival is 89% for patients with grade 1, the

combined group of patients with grade 2 and 3 have a five-year

survival of 53%.

•

Approximately 10% of tumours that recur have an increase in

the degree of malignancy.