BONE TUMORS

• Bone tumors diverse in size & gross & histologic features

• Inocuous to rapidly fatal• Critical to diagnose , stage & treat • Classified according to normal tissue

type they recapitulate or normal cell

• Benign tumors within first 3 decades of life

• Elderly malignant• Cause – unknown , genetic

alterations • Benign lesions – asymptomatic • Pain , slow growing mass , sudden

pathologic fracture• Radiology & biopsy

BONE FORMING TUMORS• Production of bone by neoplastic

cells• Tumor bone deposit as woven

trabeculae & variably mineralized

Osteosarcoma• Malignant mesenchymal tumor in

which the cancerous cells produce bone matrix

• Paget disease , bone infarcts & prior irradiation

• Metaphyseal region of long bones of extremities

• Depending on their location within bone – medullary & parosteal

Medullary / central osteosarcoma• Common, 10-20yrs, male common• Metaphysis of long bones – lower end

of femur & upper end of tibia

Based on pathogenesis – primary & secondary

• Primary – unknown etiology, evidence linking with genetic factors, period of active growth, environmental infleunces

• Hereditary retinoblastoma

• Secondary – preexisting bone diseases – paget’s disease of bone, fibrous dysplasia, multiple osteochondromas, chronic osteomyelitis, infarcts & #

• More aggressive

Medullary osteosarcoma – highly malignant• Metaphysis -> extends centrally &

expands laterally on either side breaking through the cortex & lifting periosteum -> surrounding soft tissue

• X – ray – sunburst pattern due to osteogenesis within the tumor

Codmann’s triangle – formed at the angle between elevated periosteum & underlying surface of cortex

• Clinical features – pain, tenderness & swelling

• Alkaline phosphatase raised• Metastasis – rapidly, hematogenous

route – lungs, bones, brain

Morphology • Grey white, bulky, mass• c/s – greywhite, areas of hemorrhage

& necrosis, hard & gritty if abundant osteiod & cartilage present, cystic degeneration

osteosarcoma of upper end of tibia

Osteosarcoma- Femur

• Tumor cells have large hyperchromatic nuclei , bizarre tumor giant cells

• Formation of bone by tumor cells- lace like architecture , deposited in broad sheets or primitive trabeculae

Osteosarcoma

Clincal course- • Painful & progressively enlarging

mass• Sudden fracture• X – ray –large destructive , mixed

lytic & blastic mass with permeative margins

• Breaks through cortex , lifts periosteum – reactive periosteal bone formation

• Codman’s triangle • Chemotherapy & limb salvage

therapy

Parosteal / Juxtacortical osteosarcoma• Uncommon, better prognosis• Older age grp• Lower end of femur, upper end of

humerus

MISCELLANEOUS TUMORSEwing sarcoma • 10 -15 yrs, highly malignant• Shafts & metaphysis of long bones• Arise in medullary cavity , invades

cortex & periosteum producing soft tissue mass

• Tan with areas of hemorrhage & necrosis

• Sheets of uniform small , round cells with scant cytoplasm

• Homer- Wright rosettes – around bld vessels

• Painful enlarging mass

Ewing sarcoma

Ewing sarcoma

• Plain x- ray – destructive lytic tumor with permeative margins

• Periosteal reaction produces layers of reactive bone deposited in onion-skin fashion

• Treatment chemotherapy & surgery

Giant cell tumor• Osteoclastoma• Benign but locally aggressive

neoplasm • 20-40yrs• Monocyte macrophage lineage

Morphology-• Large red brown , undergo cystic

degeneration • Uniform oval mononuclear cells with

indistinct cell membrane , grow in syncytium

• Scattered within background are numerous osteoclast type giant cells

• Necrosis , hemorrhage , hemosiderin deposition , reactive bone formation

Osteoclastoma

Osteoclastoma

• Involves epiphysis & metaphyses• Arise around knee , solitary• Arthritic symptoms• X – ray – large purely lytic , eccentric

& erode into subchondral plate , overlying cortex destroyed

Giant cell tumor - MRI

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