Osteosarcoma is a malignant bone tumor characterized by the production of osteoid bone. It is the second most common primary bone malignancy and occurs most often in the metaphysis of long bones in adolescents and young adults. The tumor may be conventional, presenting as osteoblastic, chondroblastic or fibroblastic subtypes, or may be a rare telangiectatic or well-differentiated variant. While the exact cause is unknown, risk factors include rapid bone growth, genetic conditions, radiation exposure and pre-existing bone diseases.

2.  Definition
 Introduction and brief history
 Epidemiology
 Etiology
 Pathology
 Classification

3.  A mesenchymal
malignancy that
differentiates to
produce osteoid is an
osteosarcoma no
matter how much
osteoid is produced Osteoid
Deposition

4.  Malignant tumor of
mesenchymal origin
having Spindle shaped
cells that produce osteoid
 Second most common
primary malignancy of
bone
 15% of all biopsied
primary bone tumors

5.  In 1805, the French surgeon Alexis Boyer first
used the term "osteosarcoma’’
 In 1847, the Baron Guillaume Dupuytren described
gross pathologic appearance of osteosarcoma
 Jaffe and Lichtenstein established histologic
criteria to diagnose common bone tumors

6.  In the 1970s, Dr Norman Jaffe used variety of
effective chemotherapeutic agents
 Dr William F. Enneking introduced his surgical
staging system for musculoskeletal sarcomas.

7.  In the United States, the incidence of
osteosarcoma is 400 cases per year (4.8 per
million population <20 y).
higher in blacks than in whites
higher in males than in females
 The overall 5-year survival rate is 63%

9.  Sites:
Metaphysis: 90%
Diaphysis: 8-10%
- can occur in any bone
Long Bones: 70%-80%
Distal Femur (40%)
Proximal Tibia (20%)
Proximal Humerus
(15%)
Axial Skeleton
Pelvis

10.  The exact cause of osteosarcoma is unknown
Risk factors –
 Rapid bone growth
 Environmental
 Genetic
 Pre-existing benign /malignant lesions

11.  Rapid bone growth
- increased incidence during the
adolescent growth spurt
- location in the metaphyseal area adjacent to the
growth plate (physis) of long bones
 Genetic
Li-Fraumeni syndrome (p53 mutation)
Rothmund-Thomson syndrome
Mutation of the RB gene (retinoblastoma)

12.  Environmental
Radiation – localised radiation >2000 rads
latent period -4 years to 40 years
alpha rays>beta rays
Chemicals – methylcholanthrene
acetylaminofluorene
beryllium compounds
Virus - RNA :mouse sarcoma virus
DNA :polyoma ,SV 40 virus

13.  Paget disease
 fibrous dysplasia
 enchondromatosis
 hereditary multiple
exostoses
 chondrosarcoma

14.  Gross appearance
Sclerosing or osteolytic
Typical features
metaphyseal location
variable consistency and
colour
subperiosteal spread
periosteum,epiphysis,
cartilage act as barrier

15. Gross appearance
 Greyish white colour
 Consistency varies
from
Soft and gritty to hard
 Erodes inner cortex
 Invades subperiosteal
space
 Penetrate periosteum
and invades soft tissue

16. Microscopic features
 Extensive irregular
sheets of new osteoid
 Peripheral hypercellular
stroma with anaplastic
cells forming osteoid
 Central cells entraped
by osseous tissue
become small and
rounded

17. Gross appearance
 Very vascular tumour
 Consistency soft and
friable
 Necrotic and
hemorrhagic cavities
interspersed with
fibrous tissue
 Pathological fracture
common

18. Microscopic features
 Blood containing
spaces without
endothelial lining
 Sparse osseous tissue
 Spindle cells,
anaplastic osteoblast,
giant cells are seen

19.  Anatomic location
 Degree of differentiation
 Multicentricity
 Etiology
 Histology

20.  Intramedullary (75%)
 Juxtacortical/Surface (7--10%)
 Intracortical (.2%)

21.  conventional
Osteoblastic
Chondroblastic
Fibroblastic
Small-cell
Epithelioid
 Telangiectatic
 Well--differentiated

22. Juxtacortical Osteosarcoma
 Parosteal Osteosarcoma
 Periosteal Osteosarcoma
 High Grade Surface Osteosarcoma

23.  Origin: Arises from
outer layer of
periosteum
 Usually a low grade
tumor with fibroblastic
stroma and
osteoid/woven bone

24.  Origin: Arises from
the
inner layer of the
periosteum
 Low to intermediate
grade bone with
predominant
chondroblastic
differentiation

25. Parosteal Osteosarcoma Periosteal Osteosarcoma

26.  High Grade Surface
osteosarcoma

27.  Very rare
 High grade
 confined to the cortex
 Sites: Diaphysis of
femur or tibia

28.  Synchronous Osteosarcoma:
Lesions that affect multiple bones
discovered within 6 months of each other
 Metachronous Osteosarcoma:
Lesions involving multiple bones
discovered more than 6 months apart

29.  Malignant transformation of benign condition
Paget disease
fibrous dysplasia
bone infarct
 Arising in dedifferentiated chondrosarcoma

30.  A mesenchymal malignancy that differentiates to
produce osteoid bone
 Second most common primary malignant tumor of
bone
 Site - metaphysis of long bone
 Age – adolescent (15 – 25 years)

31.  Etiology not known
 Associated risk factors –
rapid bone growth in young
pre-existing bone lesion in old age
 Most common - Conventional Osteosarcoma

33. Thank you