Osteosarcoma & Ewing Sarcoma Flashcards
What are the 4 most common primary malignancies of bone from most to least common?
MOCE:
- multiple myeloma
- osteosarcoma
- chondosarcoma
- Ewing sarcoma
Which of the 4 most common primary malignancies of bone occur in older populations?
Multiple Myeloma & Chondrosarcoma
(MOCE)
Which of the 4 most common primary malignancies of bone occur in younger populations?
Osteosarcoma & Ewing sarcoma
(MOCE)
(Primary/Secondary) malignancies of bone account for 70% of all bone malignancy
Secondary
What population is primarily affected by osteosarcomas?
Bimodal:
- <20 years (75%; primary)
- Older adults with predisposing conditions (secondary)
What is the most common primary bone tumor in children?
Primary osteosarcoma
What conditions can predispose older adults to developing a secondary osteosarcoma?
- Pagets
- Hx of radiation therapy (20 yr latency period)
- Bone infarct
What is the preferential location of osteosarcoma?
- Metaphyseal region of long bones -> extends into diaphysis
- knee (50%)
- secondary osteosarcoma common in flat bones
What is the etiology of osteosarcoma?
Mutations in tumor suppressor genes & oncogenes
Name 5 genes that could be mutated to cause osteosarcoma
- RB
- TP53
- INK4a
- MDM2
- CDK4
What type of gene is RB?
Tumor suppressor gene
What is the function of RB?
Negative regulator of cell cycle (slows/stops)
What type of gene is TP53?
Tumor suppressor gene
What is the function of TP53?
Encodes P53
What is the function of P53?
Promote DNA repair and apoptosis of damaged cells
What is the function of the INK4a gene?
Encodes p16 and p14 (tumor suppressors)
What is the function of MDM2 and CDK4?
Inhibit p53 and RB function
(Allows damaged cells to live)
What genes are overexpressed in many osteosarcomas?
MDM2 and CDK4
What are the gross characteristics of an osteosarcoma?
- progressively enlarging soft tissue mass beyond bone
- mixed blastic (ossification) & lytic (cortex destruction) mass
- irregular margins
- may lift/penetrate periosteum (aggressive Rxn)
- hemorrhagic marrow
- invasive (may metastasize)
Where do osteosarcomas frequently metastasize to?
Lungs, brain, other bones
What is the term for large soft tissue masses in the lung due to metastasis of an osteosarcoma?
Cannon ball mets
How would a patient with an osteosarcoma present clinically?
- bone pain & swelling around site of tumor
- possible palpable tumor (eg. Popliteal fossa)
- patho Fx
- Abnormal labs
(may be tired/winded if mets to lung)
What lab findings would be seen in a patient with an osteosarcoma?
- ^ESR
- ^CRP
- ^alkaline phosphatase
What are the radiographic characteristics of an osteosarcoma?
- patho Fx
- long/wide ZoT
- radiopaque mass and/or radiolucency
- aggressive periosteal reaction
- cortical destruction
What radiographic characteristic of an osteosarcoma indicates soft tissue mass extending beyond bone?
Aggressive periosteal reaction (laminated, spiculated or Codman’s triangle)
Which pattern of destruction is linked to a more aggressive type of osteosarcoma?
A) mixed
B) blastic
C) lytic
lytic
(more aggressive builds less bone)
What general pattern of destruction may be seen in an osteosarcoma?
Can be blastic or lytic or both
What is the most common primary malignancy of bone?
Multiple myeloma
What is the most common primary malignancy of bone in kids?
osteosarcoma
What is the second most common primary malignancy of bone?
Osteosarcoma
What is the second most common primary malignancy of bone in elderly patients?
Chondrosarcoma
What is the second most common primary malignancy of bone in kids?
Ewing sarcoma
What is the most common malignancy of bone?
metastatic disease
What genes are turned off or deleted in many osteosarcomas?
- RB
- TP53
- INK4a
Which primary malignancies of bones prefer to metastasize to other bones?
1 MC: Ewing sarcoma
2 MC: Osteosarcoma
Most osteosarcomas are (blastic/lytic/mixed)
blastic
An osteosarcoma presents on an x-ray as a densely blastic mass. Is this more or less aggressive than an osteosarcoma that appears purely lytic?
less
If a bone tumor presents radiographically with a soft tissue mass extending beyond the bone, is it more likely to be primary or secondary?
primary
(mets to bone rarely have soft tissue mass beyond bone)
What is the common treatment for an osteosarcoma?
- amputation + chemo/radiation therapy
- limb salvage surgery
What age group is primarily affected by Ewing sarcomas?
<20 years
What is the etiology of Ewing sarcoma?
- poorly understood
- 90% show translocation between chromosomes 11 & 22
What is an Ewing sarcoma comprised of histologically?
neuroectodermal cells:
- closely packed, small, round cells w/out obvious differentiation
- arranged in uniform sheets
- cells have little cytoplasm, w/ huge nuclei
What is the preferential location of Ewing sarcoma?
- arises in medullary cavity and grows outward
- femur, other long bones & pelvis
- mid-diaphysis of long bones
What is the most common primary malignancy of bone to metastasize to other bones?
Ewing sarcoma
How would a patient with Ewing sarcoma present clinically?
- painful enlarging masses (deep boring bone pain)
- tender, warm, swollen around site
- may mimic infection (fever, ^ESR, leukocytosis)
- unexpected weight loss
- weakness
- anemia
What is the treatment for Ewing sarcoma?
chemo/radiation therapy & limb-sparing surgery
What are the radiographic characteristics of Ewing sarcoma?
- permeative/motheaten lytic destruction
- long ZoT
- cortical disruption
- laminated/spiculated/Codman’s periosteal Rxn
- may extend to soft tissues
(can look like osteomyelitis –> send to ER)
What bone pathologies would you include in your differential diagnosis if you see aggressive bone destruction radiographically in a patient under 25 years old?
OLEO:
- osteosarcoma (aggressive kid tumor)
- Ewing sarcoma (aggressive kid tumor)
- lymphoma (any age)
- osteomyelitis (appears same; more common in kids)
What benign and malignant tumors of bone may be on your differential diagnosis for a lesion in the diaphysis?
- enchondroma
- fibrous dysplasia
- ewing sarcoma
- chondrosarcoma
