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Onco 8 OSA

sihirlifil's version from 2018-05-02 21:45


Question Answer
Ddx for OSASoft tissue swelling/injury/trauma, osteomyelitis, 1ry bone tumor
Which 1ry bone tumors are differentials (large, firm swelling right carpus, RF lameness)OSA, chondrosarcoma, fibrosarcoma, lymphoma, hemangiosarcoma, synovial cell sarcoma
Osteomyelitis: fungal, bacterial
Where do the most common bone tumors arise?Mesenchymal elements associated w/ bone (osteosarcoma)
Firbous CT (fibrosarcoma)
Cartilage (chondrosarcoma)
Fat cells (liposarcoma)
Blood vessels (hemangiosarcoma)
Hematopoietic cells of the bone marrow (plasma cell tumor, lymphoma)
What is osteosarcoma?Malignant spindle cell tumor of bone consisting of malignant stroma w/ evidence of malignant osteiod, bone, a/o cartilage formation by the tumor cells
Signalment of OSALarge/giant breeds 95%
BIMODAL AGE distrib: mid-old (8y) & young (2y)
In WHO (age) is OSA more aggressive?YOUNG!
Incidence of OSA8,000-10,000 dogs/yr
Most common 1ry tumor of bone
Etiology of OSAUnknown! ionizing radiation, bone tumor viruses (polyoma, SV-40, type C retro), chemicals, chronic irritation in healing frax, FB (metal implants, bullets), genetic predisposition, p53 tumor suppressor gene mutation
**WHERE does OSA occur?“Away from the elbow, towards the knee”. 75% appendicular
LARGE dogs: FL
Small dogs: HL!
Distal radius 40%, prox humerus, FRONT 2x BACK
Hemangiosarcoma (just lysis)
Synovial cell sarcoma (all lytic, crosses joint)
Clinical signs of OSALameness due to pain, total loss of limb fxn, muscle atrophy
Palpable mass (+/- warm, painful), soft tissue swelling
CNS deficits
Dyspnea, nasal obstruction, hge to purulent nasal d/c
Diagnosis of OSAComplete PE
Thorough ORTHOPEDIC exam! need to make sure hips ok, good candidate for amputation
CBC/Chem/UA (ALK-P!!!)
Thoracic rads 3+ views
Abd rads +/- US
Bone scan**
Diagnotic you WOULDN’T want to doBiopsy!!!
Radiographic features of OSALysis/cortical thinning
Loss of trabecular pattern
Periosteal reaction, Codman’s triangle, metaphyseal
**which type of cancer crosses joint?Synovial cell carcinoma
What do with this
Stick a needle in it, ALK-P stain very sensitive for OSA!
What are we seeing here? can look like what else?
Bone scan (nuclear scintigraphy)
Looks like osteoarthritis! (except top left). areas of increased turnover
Possible sequel of OSA?Pathologic fracture
Where does OSA most commonly metastasize?LUNG 90% at time of dx, 10% have radiographic evidence
Other sites: liver, kidneys, amputation stump, adjacent bones
Treatment of OSAIssue of life & limb… life = address metastatic dz, limb = alleviation of pain
How can we medically manage OSA? when?NSAIDs & analgesic if PALLIATIVE intent
Survival medical management of OSA4-5m (same as amputation)
When would amputation be an option?Palliative intent (same as med)
When would radiation therapy be an option?Palliative intent, survival 6 months before cancer pain breaks through
**Gold standard of careAmputation + chemotherapy
Survival times of various chemo protocols12-18m
Tx: What is limb sparing?Removal of affected bone & replacement with donor bone, or distraction techniques
Survival time limb sparing8-12m
Tx: requirements for limb sparingNo pre-existing orthopedic or neurological disease
OSA clinically & radiographically confined to leg
1ry tumor affecting <50% of the bone
Absence of pathologic fracture
Less than 360* involvement of soft tissues
Firm/definable mass vs. edematous lesion
What are the limb salvage techniques?Surgery
(limb salvage) When is surgery an option?Appendicular sites amenable to removal (digits, scapula, ulna, ribs)
(limb salvage) Surgery: what is bone allograft? when can you use?Take bone from donor (replace w/ bone or implant)
Limited to certain sites: Distal radius, proximal humerus, distal tibia
(limb salvage) Surgery: potential complicationsDecreased mobility & ROM; infection
(limb salvage) Surgery: what is distraction osteogenesis?Diseased bone is excised, patient’s own bone ist distracted to fill in gap over time
(limb salvage) How is radiation done?External beam
(limb salvage) Goals of radiationDecrease osteoclastic activity
Prognostic factors for OSASIZE: BIG = BAD
Anatomic site, location within bone (parosteal)
Bone & total ALP
Age of patient
Metastatic/Stage III
Survival WITH nodal metastasisMST = 59d
Survival without nodal metastasis318d
How common is OSA on the AXIAL skeleton?25% of OSA
Signalment of axial OSAMiddle-aged dogs, more common female
Axial OSA usually involves… (anatomic)Ribs (younger? 8m)
Skull: cranial vault, zygomatic arch, mandible, nasal cavity
How common is EXTRASKELETAL OSA?RARE! (2-3m survival)
(Where does extraskeletal OSA happen?)(Spleen, adrenal gland, eye, testicle, vag, kidney, intestine, mesentery, liver, skin, mammary gland)
How common is OSA in cats?MOST COMMON 1ry BONE TUMOR! Appendicular, axial. DSH, no gender predilection
Causes of feline OSAFractures & frax repair; trauma; radiation; vaccine (extraskeletal??)
(Other 1ry bone tumors in cats)(FSA > CSA > HSA)
Feline APPENDICULAR OSA: how common? happens in who? where?70%
Older 8-9y, HL > FL. Proximal tibia, distal femur, proximal humerus
Feline APPENDICULAR OSA: CSChronic lameness
Feline APPENDICULAR OSA: TxAmputation = pain relief, little impact on mobility, may be curative
Survival Feline APPENDICULAR OSA5+ years~! :)
Feline AXIAL OSA: in who? where?Older (10.5y) DSH
Skull > nose, mandible, rib, spine
Feline AXIAL OSA: CSVary with site! Large mass, swelling, skull deformity, stertor, nasal d/c,sneezing, exophthalmos, behavior changes, loose teeth, otitis, dyspnea, paresis, ataxia
Feline AXIAL OSA: TxSurgery + Radiation therapy (e.g. strontium on palate)
Local recurrence = euthanasia :(
Survival Feline AXIAL OSA5.5m up to or >1y

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