oncology 2 Flashcards
Ddx Bone Tumour
- Osteosarcoma (85‐90%)
- Fungal osteomyelitis
- Hemangiosarcoma
- Metastastic tumour
- Chondrosarcoma
- Histocytic Sarcoma
- Multiple myeloma
- Fibrosarcoma
Most common primary bone tumour
in dogs and cats?
osteosarcoma
are osteosarcomas more common in dogs or cats?
dogs
what % of bone tumors in dogs are osteosarcoma? what types of bones does it generally affect?
- > 85% of bone tumours in dogs
- 80% of osteosarcoma affects the long bones or appendicular skeleton
osteosarcoma signalment - breeds, age?
*Large and Giant Breeds
Age:
*Median age 7 years
*Two “peaks” in age at presentation
> 18‐24 months
> 7‐9 years
osteosarcoma presentation - what might we see?
- mild or severe
- acute or chronic
- some response to analgesics / rest
- pathologic fracture
- soft tissue swelling
common sites for osteosarcoma
- Metaphyseal region
() - Common sites:
- Radius ‐ Distal
- Humerus ‐ Proximal
- femur - distal
- Tibia – Distal or Proximal
- “Away from the elbow and towards the knee”
diagnostic approaches ;/ tools for osteosarcoma
- Signalment & History
- Physical & Orthopedic exam
- radiographic signs
- Cytology/Histopathology
radiographic signs of osteosarcoma
- cortical lysis
- extension into soft tissue
- lack of distinct border between normal and abnormal
- does not cross joint
osteosarcoma - to biopsy or not? what to do?
- Usually not necessary
- Fine needle aspirate quite sensitive
- Jamshidi/ Michelle trephine
- Clinician’s preference
- Atypical signalment, location or
radiographic appearance - Diagnosis will change treatment plan
is fna good for osteosarcoma diagnosis? is fracture an issue with this?
- Bone FNA has a 95% accuracy for diagnosis of OSA
- Can often get answer of soft tissue component
- Low risk of fracture
Risks of Bone Biopsy for animal
- increased lameness post biopsy
> can be due to pathologic fracture - contamination of biopsy tract
- increased fracture risk for RT
if we do a bone biopsy for osteosarcoma, how do we interpret the findings? how should we take the biopsy?
- non-diagnostic sample
- Reactive bone does NOT = benign disease
Risks of Bone Biopsy - biopsy through the center of the radiographic lesion
Where is it… how do we answer this question for osteosarcoma?
staging
when we stage osteosarcoma, what do we commonly see? what is the purpose of staging?
- > 90% cases have micrometastasis at the time of diagnosis
- Staging is done to determine if there is evidence of gross metastasis
- Where?
- Lungs
- Bone
- Lymph nodes
