Tumors of bone. - Cause usually unknown (Primary, idiopathic) - Genetic factors may play a role (p53 and RB mutations) - Bone infarcts, trauma, osteomyelitis,

Tumors of bone

Tumors of bone

- Cause usually unknown (Primary, idiopathic)

- Genetic factors may play a role (p53 and RB

mutations)

- Bone infarcts, trauma, osteomyelitis, Pagets

disease, radiation and metal prosthesis

predispose to tumors

Tumors of bone- Clinical

presentation

- Incidentally

detected

- Swelling and pain

- Pathological

fracture

Interpret bone tumors with full

knowledge of

- Clinical picture

- Radiology and imaging

- Pathological findings

Tumors of bone

- Diverse in their gross and morphologic features,

and clinical behavior.

- Benign tumors outnumber malignancies and are

commoner in young

- Classification is done on the basis of tissue of

origin

Bone tumors

Histologic type Benign Malignant

Hematopoietic (40%) Myeloma, lymphoma

Chondrogenic (22%) Osteochondroma, chondroma, chondroblastoma, chondromyxoid fibroma

Chondroscarcoma, dedifferentiated and mesenchymal chondrosarcoma

Osteogenic (19%) Osteoid osteoma, osteoblastoma Osteosarcoma

Unknown (10%) Giant cell tumorEwing sarcoma, giant cell tumor, adamantinoma

Histiocytic Fibrous histiocytoma Malignant fibrous histiocytoma

Fibrogenic Fibroma Desomplastic fibroma, fibrosarcoma

Notochordal Chordoma

Vascular HemangiomaHemangioendothelioma, hemangiopericytoma, angiosarcoma

Lipogenic Lipoma Liposarcoma

Neurogenic Neurilemmoma (schwannoma)

Tumors and tumor-like conditions of bone- Diverse in their gross and morphologic features, and clinical behavior.- Benign tumors outnumber malignancies and are commoner in young- Specific tumor types have preferential age and sex distribution- Specific tumor types preferentially involve specific bones and specific regions within a bone

Metaphysis

10 20 30 40 50 60 70 yrs

Osteogenic Sarcoma

10 20 30 40 50 60 70 yrs

Chondrosarcoma

Bone tumors

All bone tumors should be studied along with x

rays

- Osteochondroma is the commonest benign tumor

- Osteosarcoma is the commonest non-hematopoietic

malignancy

- Specific tumors target specific bones and sites and age

groups

- Osteosarcomas are more common in adolescence and

arise from

metaphysis around the knee.

- Chondrosarcomas and giant cell tumors arise in epiphysis

- Ewings sarcoma arises in diaphysis

Histologic grade is the most important prognostic

factor of a bone sarcoma

Bone tumors













Osteoid osteoma- Benign bone tumor seen often in teens and young adults

- < 2 cm diameter and have predilection for cortex of long

bones

- Painful lesions and can mimic osteomyelitis (PGE2)

- Well circumscribed mass of woven bone rimmed by

osteoblasts

- This is called the nidus and is surrounded by reactive

bone

Osteosarcoma

- Malignant mesenchymal tumor in which cancerous cells

produce bone matrix

- Most common non-hematopoietic bone tumor

- 75% occur before the age of 20 years. Second peak in elderly

- Commoner in males (1.6:1)

- Arises from metaphysis of long bones. 60% arise around the

knee

- Patients with hereditary retinoblastomas have a 1000 fold risk

- Metastasizes through hematogenous route (90% to lungs)

- Advances in treatment (chemotherapy and limb salvage

therapy) has improved long term survival to 60-70%

10 20 30 40 50 60 70 yrs

Osteogenic Sarcoma

Osteosarcoma - subcategorization

Based on Subtypes

Location Intramedullary / intracortical / periosteal etc

Differentiation Well / poorly

HistologyOsteoblastic / chondroblastic / fibroblastic, telangiectatic / giant cell / small cell

OthersSolitary / multicentricPrimary / secondary

Osteosarcoma

Gross: Bulky, gritty, hemorrhage and necrosis,bone

destructive and spreading in different directions

Microscopy: - Bizarre tumors cells with pleomorphic nuclei

- Multinucleated giant cells

- Formation of “lacy osteoid”

- Formation of other types of matrix

- Conspicuous vascular invasion - metastasize to lungs, brain

X-ray:- Large destructive lytic and osteoblastic mass with infiltrating

margins

- Lifts periosteum (Codman triangle) and produces reactive

periosteal bone formation

Tumor grading

- Low grade- High grade

- Cell

pleomorphism

- Tumor

differentiation

- Necrosis

- Mitotic activity

Hematogenous spread is very common and 10-20% have pulmonary metastases at the time of

diagnosis

Bone tumors













Benign cartilage tumors:Osteochondroma: Bony spur / exostosis. Mushroom shaped bone projection

covered by cartilage cap

Chondroma: - Enchondroma ( intramedullary) or juxtacortical- Usually solitary and metaphyseal in short tubular bones and < 3 cms dia- Multiple tumors form part of Olliers disease (enchondromatosis)- Develop from rests of growth plate cartilage- Contain well circumscribed nodules of cartilage and cytologically benign chondrocytes- Endochondral ossification is seen at periphery- X-ray shows typical “O ring” sign - Malignant transformation more common in Ollier disease

Chondrosarcoma- Malignant tumors that form neoplastic cartilage

- Subtypes:a) Intramedullary and juxtacortical

b) Conventional (hyaline / myxoid), clear cell,

dedifferentiated, mesenchymal

c) Low grade to high grade

- Usually seen in patients above 40, more in men (2:1)

- More often in central parts of skeleton

- Large bulky tumors with glistening cut surface with

central necrosis

- Tumor spreads by pushing margins

- Low grade tumors almost similar to enchondromas

- High grade show marked pleomorphism and bizarre

morphology

- Spread preferentially to lungs and skeleton

Bone tumors













Ewing Sarcoma and PNET (primitive neuro-

ectodermal tumor)

- Primary malignant small round cell tumors of bone and soft

tissue

- Share similar neural phenotype and chromosomal

translocation

- Second commonest malignant non-hematopoietic bone

tumor in children

- Children 10-15 years old, boys more affected. Diaphysis of

long bones

- 85% show t(11;22)

- Tumors arise from medullary cavity, invade cortex, spread

to soft tissue

- Comprised of small round cells slightly larger than

lymphocytes

- Cells are rich in glycogen.

- May show Homer-Wright rosettes. Necrosis is seen

- Xray shows typical layers of reactive bone (“Onion-skin”

pattern

- Combination chemotherapy has improved 5 year survival to

75%

Gross:

- Arise in medullary cavity

(diaphysis)

- Invade cortex and

periosteum

- Tan white colour with

hemorrhage and necrosis

Microscopy:

- Sheets of uniform

small cells

- Rosettes (Homer-

Wright)

- Few mitotic figures

Giant Cell Tumor:

(Osteoclastoma)

- Contains numerous osteoclast type of giant cells (monocyte

macrophage)

- Benign but locally aggressive

- Patients between 20 to 40 years

- Involve both epiphysis and metaphysis and are common in

long bones

- Xray shows typical soap bubble appearance and thin

reactive shell

- Tumor comprised of oval mononuclear cells growing in

sheets mixed with osteoclast type of giant cells with more

than 100 nuclei

- Necrosis and hemorrhage common

- Biologically unpredictable tumors

Involve both epiphysis and

metaphysis

Large purely lytic - “Soap

bubble” tumors

Gross:

- Large, red-brown

- Hemorrhage and

cystic degeneration

- Uniform mononuclear

cells in sheets with

increased mitoses

- Numerous osteoclast

type of giant cells with >

100 nuclei

Documents

Tumors of bone. - Cause usually unknown (Primary, idiopathic) - Genetic factors may play a role (p53 and RB mutations) - Bone infarcts, trauma, osteomyelitis,