Bone neoplasia Flashcards
Osteosarcoma
Most common primary bone tumor in dogs
1st age peak @ 1-2y, 2nd @ 8-10y
Monostotic
Predilection sites of of osteosarcoma
Metaphysis of dogs
Away from elbow- distal radius* and prox humerus
Towards the knee- distal femur and prox tibia
Signalement of osteosarcoma
Large and giant breeds
Rad findings with OSA
Aggressive: moth-eaten/ permeative osteolysis
Spicualted periosteal proliferation (classic)
How do you stage OSA
3 view (rt. lat, lt. lat and VD)
75-90% of cases metastasize
Metastatic bone dz
Polyostotic and monostotic
Diaphysis and metaphysis
Aggressive
Neoplasms that metastasize to bone
Carcinoma: mammary, lung, liver, thyroid, urinary bladder/ prostate gland
OSA
Pathologic fracture
Occurs without abnormal/ overt trauma
Secondary to weakening of bone from underlying dz (neoplasia or second hyperparathyroidism)
Sublingual toe lysis
Lysis → neoplasia → cell carcinoma or melanoma
if not neoplasia then pododermatitis
Signalment of toe lysis
Large lesion of the distal phalanx
Large breed dogs with black haircoats (SCC)
Bacterial Osteomyelitis
Early: ST swelling
10-14d before periosteal reaction seen (extend along the diaphysis and smooth)
Fungal Osteomyelitis
Monostotic or polystotic (aggressive)
Accompanying systemic dz (fever, lymphadenopathy, pulmonary nodules)
Where is fungal osteomyelitis found?
Younger animals
Metaphyseal region
Causes of mycotic osteomyelitis
Coccidiomycosis and blastomycosis
Osseous sequestrum
Sequestrum (centralized peice of dead bone)
Lucent zone surrounding sequestrum (purulent and granulation material)
Involucrum* (Scelerotic bone adjacent to lucency)
+/- cloaca (with draining tract)
Hypertrophic osteopathy (HO)
Occurs secondary to systemic dz (thoracic mass, granulomatous dz, HW dz, parasites, abdominal mass)
Indeterminate and reversible
Radiographic findings associated with HO
Diffuse ST swelling
Solid periosteal proliferation (palisading/ smooth)
Palisading periosteal reaction of HO
Outer aspect of 2nd and 5th digits → skips cuboidal bones/ joints → progresses proximally along limb
Nuclear medicine
Requires nucleotides (heavily regulated)
Sensitive and specific
Basic procedure of nuclear medicine
Administration of a very small amount of gamma ray- emitting radioisotope
Short half life of 6 hr and excreted in urine, feces and sweat
Radioisotope
Administered IV for most common studies: thyroid or bone scintigraphy
Detected with a gamma camera
Bone scintigraphy
Requested when source of lameness is ill-defined (equine)
Tx-99m MDP used for IV injection
Thyroid scintigraphy
Feline hyperthyroidism dx
Evaluates extent and severity of thyroid tissue
Tc-99m pertechnetate IV
Compound tx for thyroid scintigraphy
Radioactive iodine I-131
Equine bone scans
Lab coat, latex gloves, disposable shoe covers and lead sheet
Hyperthyroid cat thyroid scan
Lab coat and latex gloves
Isolating patients after scans
Urine, feces and blood handled differently
60h before stall can be cleaned
Patient is scanned for external radiation exposure before release from hospital
Isolation of patients after feline I-131 tx
Radiation isolation ward
Urine and feces collected and held for 10 t1/2
T/F: Nuclear medicine cannot be used to gather detailed info about patient anatomy
TRUE
