Canine Hyperthyroidism

Question 1

What are the two cell types that can give rise to thyroid cancer in the dog?

Answer 1

• follicular (70%), stains (+) for thyroglobulin
• parafollicular/ c-cell/ medullary, stains (+) for calcitonin

Question 2

Which molecular pathway has been implicated in the development of thyroid carcinoma in the dog?

Answer 2

PI3K/ Ark pathway
- VEGF = important target for TSH activation of angiogenesis in thyroid cancer cell lines

Question 3

What are some common locations for ectopic thyroid carcinoma?

Answer 3

sublingual, mediastinum, heart- base

Question 4

What are some common clinical signs of canine hyperthyroidism?

Answer 4

vomiting, diarrhea, hypertension, weight loss, hyperactivity, panting, PU/PD

Question 5

What’s the most sensitive / specific imaging modalities for canine hyperthyroidism?

Answer 5

CT = most specific
MRI = most sensitive.
99mTcO4: good for ectopic/ metastatic (plain rads or CT is still better for metastasis)

Question 6

What are some treatment options and prognosis for canine hyperthyroidism?

Answer 6

• Surgery, up to 38m if favorable factors present
• RT, definitive intent, mean progression free interval = 45m; palliative RT
• Chemo: platinum based
• 131I, MST 12-34m
• medical / methimazole

Question 7

What are some considerations for dogs with hyperthyroidism that undergo surgery?

Answer 7

• may need to pretreat with atenolol to prevent arrhythmia/ thyroid storm
• anti-hypertensives: ACEi and/or amlodipine

Question 8

What’s thyroid storm?