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Bone Cancer (Osteosarcoma) is the most common primary malignant
bone tumour, excluding myeloma and
lymphoma. There
is a predilection for the metaphyseal region of
tubular long bones.
50% of
bone cancer cases occur around the
knee. Bone Cancer (osteogenic sarcoma) is a
malignant connective (soft) tissue tumor whose
neoplastic cells present osteoblastic
differentiation and form tumoral bone.
In children, 5% of
all cancers are seen as
bone cancer. 75% of all
bone cancer cases occur in patients below the age of 20. Looking
at the distribution of cases by age from here, a
second peak in bone cancer incidence occurs in the elderly,
usually associated with an underlying bone pathology
such as Paget's disease, medullary infarct, or prior
irradiation.
In all
bone
cancer
cases, the
bone tumor may be localized at the metaphyseal end of the long bones. Most often it affects the upper end of
tibia or humerus, of lower end of femurus.
The
bone tumor
is solid, hard, irregular ("fir-tree" aspect on
X-ray examination) due to the tumor spicules of
calcified bone radiating in right angles.
Surrounding tissues are infiltrated.
Microscopically: Bone tumor cells are very pleomorphic
(anaplastic), some bone tumor cells are giant, numerous atypical
mitoses. These cells produce osteoid describing
irregular trabeculae (amorphous, eosinophilic/pink)
with or without central calcification (hematoxylinophilic/blue,
granular) - tumor bone. Tumor cells are included in
the osteoid matrix. Cartilage may be present.
Presence of immature blood vessels (sarcomatous
vessels lacking endothelial cells) favors the
bloodstream metastasizing.
Bone Cancer Symptoms
Symptoms of
bone
cancer will first appears as a lump in long bones.
Muscles in the area will start to become weaker and
may appear to "shorten" or feel tight. some
individuals report the sensation upon palpation that
the muscles themselves actually detach from the cancering
area.
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