Endocrine Neoplasia

Question 1

What are the 2 zones of the adrenal and what types of tumors occur there?

Answer 1

Cortex: adenoma or adenocarcinoma (functional or nonfunctional)
Medulla: pheochromocytoma (functional or nonfunctional)

Question 2

What are the types of functional adrenal cortex tumors?

Answer 2

Increased cortisol: Cushing’s
17-hydroxyprogesterone: Atypical Cushing’s
Aldosterone: Conn’s syndrome (cats)

Question 3

What type of adrenal tumor is more likely to invade the caudal vena cava?

Answer 3

Pheochromocytoma

Question 4

What is the best treatment for adrenal tumors?

Answer 4

Surgery

Question 5

What are the clinical signs associated with adrenal tumors?

Answer 5

Signs for Cushing’s disease
Syncope (pheochromocytoma)
None (incidental finding when imaging the abdomen)
Blood pressure not reliable

Question 6

How do we screen for/diagnose Cushing’s?

Answer 6

Screening - urine cortisol: creatinine
Diagnosis - low dose dex suppression

Question 7

What is the diagnostic test for a pheochromocytoma?

Answer 7

Urine normetanephrine: creatinine ratio

Question 8

What is the diagnostic challenge of adrenal tumors if LDDS is negative and catecholamines are negative?

Answer 8

Could be atypical Cushing’s
Could be nonfunctional
Could be false negative

Question 9

What should be done preoperatively for adrenal tumors?

Answer 9

Ultrasound
CT
Looking for vascular (caval) invasion
Blood type, functional type

Question 10

What are dogs with HAC at risk for with adrenal surgery? How can those risks be managed?

Answer 10

Infection (perioperative cefazolin)
Thromboembolic disease (anti-coagulants controversial)
Dehiscence

Question 11

How do we preoperatively manage dogs with a pheochromocytoma?

Answer 11

Phenoxybenzamine (alpha adrenergic antagonist) - treats hypertension
Atenolol (beta adrenergic antagonist) if tachycardia present - do not use alone

Question 12

What are the 3 surgical approaches for adrenalectomy?

Answer 12

Ventral midline
Flank
Laparoscopy

Question 13

How is an adrenal tumor with an extensive tumor thrombus best treated?

Answer 13

SRT

Question 14

What should be done post-adrenalectomy?

Answer 14

Continue IV fluids
Proper analgesia
Monitor Na, K, glucose
Monitor BP
Perform ACTH stim morning after

Question 15

What do ACTH stim results post-op tell you about adrenalectomy success?

Answer 15

Question 16

What is the prognosis of adrenal tumors?

Answer 16

Mortality up to 26%

Question 17

What are prognostic indicators of adrenal tumors?

Answer 17

Larger = worse
Invasion of vena cava
Emergency surgery = 50% mortality
Diagnosis of adrenocortical adenocarcinoma versus pheochromocytoma NOT prognostic

Question 18

What is the relevance of incidental adrenal mass findings?

Answer 18

All lesions > 2cm are malignant (rec removal)
If lesion < 2cm and no clinical signs or invasion (rec careful monitoring)

Question 19

What percentage of canine thyroid tumors are malignant? Functional?

Answer 19

80 - 90%
10 - 29% are functional

Question 20

How are canine thyroid tumors diagnosed?

Answer 20

Palpation - assess how freely moveable
Imaging - CT, US, MRI
Cytology

Question 21

How do we stage canine thyroid tumors?

Answer 21

Chest rads of CT
CBC/Chem/blood type
FNA LNs
T4
Laryngeal exam at induction

Question 22

What are possible complications of thyroid tumor surgery?

Answer 22

Hemorrhage and anemia (highly vascular)
Hypothyroidism
Laryngeal paralysis
Hypoparathyroidism
Aspiration pneumonia

Question 23

What are the prognostic factors of canine thyroid tumors?

Answer 23

Freely moveable: ST 3y
Invasive: ST 6-12m
>20cm = poor
Vascular invasion = poor

Question 24

What are treatments for canine thyroid tumors?

Answer 24

RT (MST 2-3y)
SRT for non-resectable (MST 1y)
I131 (MST 30m)
Chemo (unknown benefit)

Question 25

How common are insulinomas?

Answer 25

Most common in ferrets Occasional in dogs (most are malignant, metastasize, rarely get a cure) Rare in cats

Question 26

How are insulinomas diagnosed?

Answer 26

Whipple's triad: hypoglycemia, neuroglycopenic signs, resolution of clinical signs with glucose supplementation *Paired insulin concentration is measured on the serum in which hypoglycemia is documented*

Question 27

What insulin concentration is diagnostic for an insulinoma?

Answer 27

Above the normal range

Question 28

What is the best imaging for insulinomas?

Answer 28

US: 35 - 69% sensitivity CT *PET CT with FDG doesn't work*

Question 29

What is the treatment of choice for an insulinoma?

Answer 29

Surgery

Question 30

What adverse effects can occur with surgical excision of an insulinoma?

Answer 30

Pancreatitis from manipulating the pancreas If pancreatic and accessory pancreatic duct are removed, dog will have to be treated for EPI Patient may have DM (need insulin lifelong)