Osteosarcoma (Complete) Flashcards
Define osteosarcoma
Type of primary malingant bone tumor
Osteosarcomas are derived from what type of cells?
Mesenchymal cells
How common is osteosarcoma compared to other bone cancers?
Most common primary bone tumour in children and adolescents
Osteosarcoma is more common in which sex?
Male
What are the main risk factors for osteosarcoma?
Radiation exposure or chemotherapy
Genetic conditions:
* Li-Fraumeni Syndrome
* Retinoblastoma
* Rothmund-Thomson Syndrome
Chronic osteomyelitis
Bone infarcts
Name 3 genetic syndromes associated with increased risk of osteosarcoma
Li-Fraumeni Syndrome
Retinoblastoma
Rothmund-Thompson Syndrome
Define Li-Fraumeni Syndrome
Hereditary condition affecting tumor suppesor protein which greatly predisposes individuals to cancer
What is Rothmund-Thompson Syndrome?
Autosomal reccesive condition affecting skin, bones, hair and teeth
What are the features of osteosarcoma within the following grades:
G1
G2
G3
G1: Low-grade (Cells similar to normal bone)
G2: High-grade, abnormal cells
G3: High-grade, cells very different to normal bone
What are the features of stage 1A osteosarcoma?
Tumor located in original bone <8cm across
What are the features of stage 1B osteosarcoma?
Located in original bone >8cm across
What are the features of stage 2 osteosarcoma?
Located in original bone but cells are high-grade
What are the features of stage 3 osteosarcoma?
Tumor spread to multiple places in original bone
What are the features of stage 4 osteosarcoma?
Tumor has spread outside of original bone
What are the main signs/symptoms of osteosarcoma
Demographic:
Young (Under 25)
Male
Prolonged bone pain
- Progressively worsens over span of weeks/months
- Worse at rest and at night
Bone swelling
- Typical in long bones
- Firm, warm, ocassionally tender to touch
Pathologic fracture
- Difficulty weight bearing due to pain
Limitted range of motion
Bone pain in osteosarcoma can often be mistaken for?
Growing pains
What are the most common locations for osteosarcoma to form?
Knee (60%)
Proximal humerus
What differentials should be considered alongside osteosarcoma?
Ewing’s sarcoma
Chondrosarcoma
Lymphoma of bone
Non-ossifying fibroma
How can Ewig’s sarcoma be differentiated from osteosarcoma?
Similar presentations however more likely to have constitutional sypmtoms (e.g. fever and night sweats)
Often presents with soft tissue mass on shaft of long bones versus knee
Elevated ESR and LDH more common vs osteosarcoma
Onion skin appearance on x-ray
Small rounds cells and CD99+ on histology
How can chondrosarcoma be differentiated from osteosarcoma?
More likely to occur in adults (>40 years).
More likely to occur in pelvis, shoulder or ribs
Lytic lesions with fluffy calcifications on XR
Malignant chondrocytes vs mesenchymal cells on histology
How can lymphoma of the bone be differentiated from osteosarcoma?
More likely to have constitutional symptoms and weight loss
How can non-ossifying fibroma be differentiated from osteosarcoma?
Asymptomatic, radiolucent lesion often found incidentally on imaging
What investigation should be ordered in patients with suspected osteosarcoma?
Urgent x-ray within 48 hours for any young person with unexplained bone pain or swelling
What findings on x-ray are suggestive of osteosarcoma?
Sunburst appearance (New bony growth with periosteal reaction)
Codman’s triangle: Elevated periosteum
