Bone neoplasia

Question 1

Osteosarcoma

Answer 1

Most common primary bone tumor in dogs
1st age peak @ 1-2y, 2nd @ 8-10y
Monostotic

Question 2

Predilection sites of of osteosarcoma

Answer 2

Metaphysis of dogs
Away from elbow- distal radius and prox femur
Towards the knee- distal femur and prox tibia

Question 3

Signalement of osteosarcoma

Answer 3

Large and giant breeds

Question 4

Rad findings with OSA

Answer 4

Aggressive: moth-eaten/ permeative osteolysis
Spicualted periosteal proliferation (classic)

Question 5

How do you stage OSA

Answer 5

3 view (rt. lat, lt. lat and VD)
75-90% of cases metastasize

Question 6

Metastatic bone dz

Answer 6

Polyostotic and monostotic
Diaphysis and metaphysis
Aggressive

Question 7

Neoplasms that metastasize to bone

Answer 7

Carcinoma: mammary, lung, liver, thyroid, urinary bladder/ prostate gland
OSA

Question 8

Pathologic fracture

Answer 8

Occurs without abnormal/ overt trauma
Secondary to weakening of bone from underlying dz (neoplasia or second hyperparathyroidism)

Question 9

Sublingual toe lysis

Answer 9

Lysis → neoplasia → cell carcinoma or melanoma
if not neoplasia then pododermatitis

Question 10

Signalment of toe lysis

Answer 10

Large lesion of the distal phalanx
Large breed dogs with black haircoats (SCC)

Question 11

Bacterial Osteomyelitis

Answer 11

Early: ST swelling
10-14d before periosteal reaction seen (extend along the diaphysis and smooth)

Question 13

Fungal Osteomyelitis

Answer 13

Monostotic or polystotic (aggressive)
Accompanying systemic dz (fever, lymphadenopathy, pulmonary nodules)

Question 14

Where is fungal osteomyelitis found?

Answer 14

Younger animals
Metaphyseal region

Question 15

Causes of mycotic osteomyelitis

Answer 15

Coccidiomycosis and blastomycosis

Question 16

Osseous sequestrum

Answer 16

Sequestrum (centralized peice of dead bone)
Lucent zone surrounding sequestrum (purulent and granulation material)
Involucrum* (Scelerotic bone adjacent to lucency)
+/- cloaca (with draining tract)

Question 17

Hypertrophic osteopathy (HO)

Answer 17

Occurs secondary to systemic dz (thoracic mass, granulomatous dz, HW dz, parasites, abdominal mass)
Indeterminate and reversible

Question 18

Radiographic findings associated with HO

Answer 18

Diffuse ST swelling
Solid periosteal proliferation (palisading/ smooth)

Question 19

Palisading periosteal reaction of HO

Answer 19

Outer aspect of 2nd and 5th digits → skips cuboidal bones/ joints → progresses proximally along limb

Question 20

Nuclear medicine

Answer 20

Requires nucleotides (heavily regulated)
Sensitive and specific

Question 21

Basic procedure of nuclear medicine

Answer 21

Administration of a very small amount of gamma ray- emitting radioisotope
Short half life of 6 hr and excreted in urine, feces and sweat

Question 22

Radioisotope

Answer 22

Administered IV for most common studies: thyroid or bone scintigraphy
Detected with a gamma camera

Question 23

Bone scintigraphy

Answer 23

Requested when source of lameness is ill-defined (equine)
Tx-99m MDP used for IV injection

Question 24

Thyroid scintigraphy

Answer 24

Feline hyperthyroidism dx
Evaluates extent and severity of thyroid tissue
Tc-99m pertechnetate IV

Question 25

Compound tx for thyroid scintigraphy

Answer 25

Radioactive iodine I-131

Question 26

Equine bone scans

Answer 26

Lab coat, latex gloves, disposable shoe covers and lead sheet

Question 27

Hyperthyroid cat thyroid scan

Answer 27

Lab coat and latex gloves

Question 28

Isolating patients after scans

Answer 28

Urine, feces and blood handled differently
60h before stall can be cleaned
Patient is scanned for external radiation exposure before release from hospital

Question 29

Isolation of patients after feline I-131 tx

Answer 29

Radiation isolation ward
Urine and feces collected and held for 10 t1/2

Question 30

T/F: Nuclear medicine cannot be used to gather detailed info about patient anatomy

Answer 30

TRUE