Unit 2: 5 - Musculoskeletal Neoplasia Flashcards
What is a primary bone tumor?
Arises from bone itself
What is a secondary bone tumor?
It is metastatic to the bone
What is the most common primary bone tumor in dogs?
Osteosarcoma (85%)
What age dogs get osteosarcoma?
There is a subset of juveniles that get it (18-24 months)
But the majority are 7-10 years old
What breeds predominantly have osteosarcoma?
Large and giant breeds;
It is rare in cats
What is the prevalence of osteosarcoma in the appendicular, axial, and extraskeletal locations in the dog?
Appendicular (75%) > Axial (25%) > Extraskeletal
What specific locations is osteosarcoma most commonly found in in dogs?
Distal radius and proximal humerus
Where on the bone does osteosarcoma prefer in dogs?
Metaphysis
What does it mean when we say that osteosarcoma is monostotic?
It is limited to one bone
Generally, we can say that osteosarcoma in dogs likes to be _____ from the elbow and _____ the knee.
away, towards
Other than the distal radius and proximal humerus, what are 2 other locations where osteosarcoma can be found in dogs?
Distal femur, proximal tibia
T/F: Osteosarc is highly metastatic in dogs.
True
>90% of osteosarc metastasis is to the _____ in dogs.
lungs
Osteosarc is the most _____ bone neoplasm in cats, but it is still _____ overall.
common, rare
What is the prevalence of appendicular vs. axial osteosarc in cats?
Appendicular (50-60%) > Axial (40-45%)
What is the metastatic rate of osteosarc in cats?
10%
What is the prognosis for osteosarc in cats?
Prolonged survival with amputation alone (>64 months)
Which location in cats has a worse prognosis for osteosarc?
axial
What is the most common location for a chondrosarcome?
tibia
What are 2 differentials for secondary bone neoplasia?
- Multiple myeloma
- Carcinomas
What neoplasms are polyostotic and what does this mean?
Joint neoplasms;
Can be involved with more than 1 bone
What are the 3 common joint neoplasms?
- Synovial cell sarcoma
- Histiocytic sarcoma
- Synovial myxoma
Where do synovial cell sarcomas like to grow and what breeds are prone to these?
Elbow and stifle;
Golden Retrievers
What is the metastatic rate for histiocytic sarcomas?
What breeds are prone to getting them?
High;
Rottweilers, Bernese Mountain Dogs
What breed is prone to synovial myxomas?
Dobermans
What changes on a chemistry would be negative prognostic indicators with a bone neoplasm?
Elevated ALP and monocytosis
What is osteolysis?
Breakdown or dissolution of bone due to injury or disease
What 6 bone conditions can have osteolysis?
- Neoplasia
- Fungal osteomyelitis (Blastomycosis)
- Bacterial osteomyelitis
- Bone cysts
- Avascular necrosis
- Hypertrophic osteopathy
Obtaining a diagnosis for a bone tumor is often times _____.
presumptive
What diagnostics are done to confirm a bone tumor?
- FNA with cytology
- Biopsy
- +/- tissue culture/susceptibility
How often are FNAs diagnostic for bone tumors?
85%
How accurate are FNAs for a bone tumor, and how is this increased?
70%, higher with ultrasound guidance
What are the types of biopsies that can be taken for a bone tumor?
Closed (jamshidi or Michele trephine)
Open
Where do you want to obtain a bone biopsy from in relation to the tumor?
At the center of the lesion
How does chemo affect survival time for a bone tumor?
Prolongs it
What is the minimum margin for bone tumor removal?
Minimum 3 cm
What is amputation?
Removal of an appendage or part of an appendage
What are 6 indications for amputation?
- Neoplasia
- Trauma
- Congenital malformation
- Peripheral nerve trauma
- Intractable infection
- Ischemic necrosis
What are 2 types of intractable infections that can indicate that an amputation is needed?
Gangrene, orthopedic
What are 3 types of ischemic necrosis that can indicate that an amputation is needed?
Frostbite, burns, trauma
What are 4 contraindications for amputation?
- Ortho exam shows no need
- Neuro exam shows no need
- BCS
- Owner preference
T/F: Body size (i.e. giant breeds) are a contraindication for amputation.
False;
May just be slower to adapt but can recover just fine
What are the 3 types of thoracic limb amputations?
Which is the only one that should realistically be performed and what is the difference?
- Forequarter - takes scapula –> ONLY ONE THAT SHOULD BE DONE
- Shoulder disarticulation
- Mid-humeral
Where should the incision for a forequarter amputation be made?
Incision along spine of scapula, around proximal brachium
What should be submitted if a forequarter amputation is being removed due to a tumor?
Axillary and prescapular LNs
What is a partial scapulectomy?
Preserves acromion
What is a subtotal scapulectomy?
Preserves glenoid/shoulder joint
What is a total scapulectomy?
All of the scapula is removed
What is an ulnectomy?
Removal of only part of the una
What are the 2 types of pelvic limb amputations?
Which is the only one that should be performed?
- Coxofemoral disarticulation –> remove at hip joint –> ONLY DO THIS ONE
- Mid-femoral
What is the approach for a coxofemoral disarticulation?
Incision flank fold to ischiatic tuberosity, semicircular, curving mid-femur laterally
What should be removed and submitted if a coxofemoral disarticulation is done due to a tumor?
Popliteal LNs
What is an acetabulectomy?
En bloc resection of the acetabulum with the limb
When doing a hemipelvectomy, a partial (up to 1/3) _____ can also be done.
sacrectomy
What are 5 indications for a digit amputation?
- Neoplasia
- Self-mutilation
- Trauma
- Deep infection/migrating FB
- Congenital
What are the tumor types that can occur in the digits of a dog and what is their relative frequency?
SCC > Melanoma > OSA, MCT, STS
What are the tumor types that can occur in the digits of cats and what are their relative frequencies?
SCC > FSA > adenocarcinoma > OSA, HSA > MCT
What is lung digit syndrome?
If you find a digit tumor in cats, chest rads are indicated because cats more commonly have a primary lung tumor with secondary metastasis to the digits than the other way around.
What are the weight-bearing digits?
3 and 4
What is a partial foot amputation?
Removal of 2 adjacent digits en bloc with or without MC or MT bones
What are the 4 declaw techniques?
- Scalpel (#11 or #15)
- Guillotine
- Laser
- Deep digital flexor tenectomy
