Large animal and exotics

Question 1

Answer the following questions regarding bovine leukemia virus and lymphoma:

1. The majority of patients with bovine LSA are what grade and cellular size?
2. What variant of LSA is more commonly assoc. with enzootic, BLV-associated LSA than sporadic form?
3. The BLV is what type of virus and how is it transmissible?
4. Is the sporadic form of bovine LSA associated with BLV?
5. What are the CS associated with the sporadic form?
6. Which form of bovine LSA is associated with BLV?
7. What are the viral genes associated with BLV?

Answer 1

1. high grade and diffuse large cell and its cleaved variant most common
2. Cleaved variant with high MI
3. oncornavirus: RNA retrovirus
   Contagious and transmissible between herds (both horizontal and vertical transmission)
4. not associated with BLV
5. Generalized lymphadenopathy +/- BM involvement in calves
   o Thymic form (calves 6 mo to 2 years)
   o Cutaneous form (1-3 years)
6. Endemic form associated with BLV
   o CD5+ B cell lineage (with surface IgM)
   o Dairy cattle, typically older (>4 years)
   o Long incubation
   o 30% of BLV have persistent lymphocytosis, which is polyclonal
   o look for gp51 – only 1.7% BLV positive cattle have LSA (sources say 0.1-10%)
7. gag, pol, pro, env + Tax and Rex

Question 2

Answer the following questions regarding Tasmanian devil facial tumor disease?

1. T/F: Tumor karyotype is highly conserved despite geographical location, age or sex?
2. Describe the karyotype in regards to chromosomes/autosomes?
3. What happens to MHC?

Answer 2

1. True
2. Normal devils: 6 pairs of autosomes and a pair of sex chromosomes
   Tumor DNA: loss of part or all of 3 autosomes, addition of 4 marker chromosomes
3. DFTD cells down regulate expression of MHC- escape immune system

Question 3

Answer the following questions regarding Tasmanian devil facial tumor disease?

1. What is the response to chemotherapy?
2. What is the metastatic rate and MST?

Answer 3

1. Does not respond to VCR, doxo, or carbo
2. 65% metastatic rate (LN, lungs, kidney)
   most die within 6 months of infection

Question 4

What is the difference in the chromosomes in TVT compared to what the normal dog chromosome # is?

Answer 4

Normal dogs: 78 chromosomes, all but 2 are acrocentric (the 2 sex chromosomes)

TVT: 57-59 chromosomes, incl. 15-17 submetacentric (fusions) and 40-42 acrocentric – total DNA is close to normal

Question 5

In the case of Scottish cows with papilloma virus, what inciting cause would increase the risk for neoplastic transformation?

a. Bracken fern
b. UV radiation
c. high fiber diet
d. aflatoxin
e. insecticides

Answer 5

a. Bracken fern cow GI carcinoma

Bracken fern + BPV-1 or -2 can lead to bovine enzootic hematuria-associated bladder tumors (benign or malignant, epithelial or mesenchymal; carcinomas most common)

Order is important: virus is an initiator and bracken fern is a promoter

Question 6

1. What is the most common gastric tumor in the horse?
2. Most common hematologic changes with equine gastric tumor?
3. MST?

Answer 6

1. SCC (79%)
2. CBC: anemia (37%), hypercalcemia was less common (25%)
3. Median time from onset of signs to death = 4 weeks

Question 7

1. What is the MTD doxo dose in horses?

2. What is the most common tumor to respond and what is the RR for doxo in the horse?

Answer 7

1. MTD = 75mg/m2 (recommended dose = 70mg/m2)
2. 47% ORR: best for LSA (100%) and carcinomas (100%)
   No responses in melanoma

Question 8

Equine LSA:

1. What is the most common breed
2. What is the most common form of LSA?
3. What is the most common immunophenotype?

Answer 8

1. Quarterhorses were the most common breed
2. Multicentric LSA most common, followed by cutaneous then gastric
3. T-cell rich large B-cell

Question 9

Equine MCT:

1. What do they most commonly appear as and what location?
2. Most common breeds?
3. Benign or malignant most commonly?
4. KIT staining common or rare?
5. Are they associated with clinical disease?
6. Multicentric MCTs in horses can be described as?

Answer 9

1. Predominantly solitary dermal tumors; head most common location
   Can uncommonly develop histiocytic-like atypical tumors
2. Arabians overrepresented
3. About 2/3 are considered benign; 1/3 are poorly differentiated (these are more likely to have aberrant KIT staining)
4. Aberrant KIT staining rare (12%)
   Kit staining pattern and histologic features were not associated with poor clinical outcome or abnormal tumor behavior.
5. Associated clinical disease was uncommon and no tumors exhibited malignant behavior.
6. cutaneous, CD117+ MCTs on multiple limbs, causing draining tracts and distal limb SQ edema

Question 10

1. What would be the top 3 differentials for a rabbit with a mediastinal mass?
2. What would be the best treatment?
3. What are the clinical signs associated with mediastinal masses in rabbits?

Answer 10

1. Thymoma (most common), thymic LSA, abscess, thymic hyperplasia, thymic hemorrhage, mediastinal cysts, thymic amyloidosis
2. Hypofractionated RT (6 fr, 40 Gy total): all achieved CR, no AEs, MST not reached (YES, do it!)
   Another report, traditional RT = MST 313 days (727 days excl. anesthetic deaths)
   • Surgical mortality up to 71% (NO, don’t do it!)
3. Clinical signs: dyspnea, tachypnea, bilateral exophthalmos, edema of the head/neck
   o PNS: IMHA, dermatoses

Question 11

Insulinoma in ferrets:

1. What % of all tumors in this species?
2. What are the most common CS?
3. What % have concurrent adrenocortical tumors and multiple pancreatic nodules?
4. Is hypoglycemia or increased insulin common?
5. MST for pancreatic nodulectomy?
6. MST for partial pancreatectomy?

Answer 11

1. 25% of all tumors in this species
2. Signs: difficulty rousing from sleep, collapse, drooling
3. > 50% have concurrent adrenocortical tumors; multiple pancreatic nodules more common in ferrets (85%) than in dogs (15%)
4. Hypoglycemia yes, but up to 20% have normal insulin
5. Pancreatic nodulectomy = DFI 8 months, mean ST 15 months
6. Partial pancreatectomy = DFI 12 months, mean ST 22 months