malignant tumor of mesenchymal cells characterized by direct formation
of osteoid or bone matrix by the tumor cells (Osteogenic sarcoma).
aetiology
somatic or acquired gene changes
TP53 tumor suppressor gene
Retinoblastoma tumor suppressor
Age, growth and height, ethnicity, genetic and familial factors
germline or inherited mutations
types
primary:due to an abnormality in bone development
secondary:due to another condition
intramedullary/juxtacortical/extraskeletal
signs and symptoms
Pain in a bone or joint that gets worse
over time, especially if the pain
interferes with sleep
a noticeable mass or lump in an arm or leg
painless swelling
Back pain or a loss of bowel or bladder
control(if the tutor is in the pelvis or at the
base of the spine)
a broken bone with no injury to explain how it occurred
Stiffness or swelling of joints
Investigations
laboratory tests
Alkaline phosphatase (ALP)
Tumour markers
Lactic dehydrogenase (LDH)
CBC
Imaging
X-rays/MRI/CT scan/
Radioisotopes scan
Biopsy
needle
core needle
fine needle aspiration
surgical
incisional
excisional
clinical features
pathological fracture
codman triangle
skip lesions
sunburst appearance
pulmonary metastasis
mass
complications
pulmonary metastasis
orbital mass
anemia
treatment
surgery
limb-salvage
removing the cancer and some surrounding normal tissue but leaving the limb basically intact
amputation
removing the cancer and all or part of an arm or leg
socioeconomic
Problems with acquiring status in a society, finding a job, etc.
Feelings of revulsion by family and society.
psychology
Anxiety, depression
PTSD
Phantom limb pain
appearance(poor body image)
chemotherapy
radiation therapy
(in certain cases)
Pathophysiology
Osteosarcoma starts at the primitive mesenchymal cells, a defect in genes
will cause it to become a cancerous cell that is marked by its production of
osteoid
tumor cells produce osteoid describing irregular trabeculae
—tumor bone. Tumor cells are included in the osteoid matrix.
osteosarcoma cells act like osteoblastic cells,as they also make
bone matrix but it is not as strong as the normal healthy one.
It is mostly local and affects metaphysis of long bones
The tumor is large, bulky, and is fading away.It Contains necrosis. New bone
formation starts at the subperiosteal space and radiates from the central mass
It is a rapidly and aggressively growing tumor. It invades the medullary cavity inward.
Destroys the cortex outwards, plus it invades close soft tissue
It does not invade epiphyseal cartilage.
Hematogenous, direct spread to lungs, other bones , brain, and liver