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 humerus
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 12

Fungal Osteomyelitis

Answer 12

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

Question 13

Where is fungal osteomyelitis found?

Answer 13

Younger animals
Metaphyseal region

Question 14

Causes of mycotic osteomyelitis

Answer 14

Coccidiomycosis and blastomycosis

Question 15

Osseous sequestrum

Answer 15

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 16

Hypertrophic osteopathy (HO)

Answer 16

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

Question 17

Radiographic findings associated with HO

Answer 17

Diffuse ST swelling
Solid periosteal proliferation (palisading/ smooth)

Question 18

Palisading periosteal reaction of HO

Answer 18

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

Question 19

Nuclear medicine

Answer 19

Requires nucleotides (heavily regulated)
Sensitive and specific

Question 20

Basic procedure of nuclear medicine

Answer 20

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 21

Radioisotope

Answer 21

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

Question 22

Bone scintigraphy

Answer 22

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

Question 23

Thyroid scintigraphy

Answer 23

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

Question 24

Compound tx for thyroid scintigraphy

Answer 24

Radioactive iodine I-131

Question 25

Equine bone scans

Answer 25

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

Question 26

Hyperthyroid cat thyroid scan

Answer 26

Lab coat and latex gloves

Question 27

Isolating patients after scans

Answer 27

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

Question 28

Isolation of patients after feline I-131 tx

Answer 28

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

Question 29

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

Answer 29

TRUE