Endocrine Neoplasia Flashcards
functional adrenal tumors of the adrenal medulla secrete
Catecholamines (Pheochromocytoma)
a functional adrenal tumor of the adrenal corext secrete
cortisol (Cushings)
other sterioids:
-17-hydroxyprogesterone (atypical Cushing)
-Aldosterone (Conn’s syndrome - cats)
an adrenal tumor of the adrenal medulla
pheochromocytoma
What is Conn’s syndrome in cats *
a functional adrenal cortex tumor that secretes Aldosterone in cats
-hyperkalemic +ventroflexion of neck
What species is Conn’s syndrome seen in *
cats
a functional adrenal cortex tumor that secretes Aldosterone in cats
T/F: Adrenal tumors are typically left sided
False- they can be right sided or left sided
can be bilateral
Adrenal tumors on what side are likely to invade into the caudal vena cava (up to 25%)
RIGHT
What adrenal tumors are more likely to invade into caudal vena cava
Pheochromocytoma
On what side is the adrenal gland really close to caudal vena cava
RIGHT SIDE
What is the best treatment for adrenal tumors
Surgery
What are the typical clinical signs for pheochromocytoma
syncope
T/F: blood pressure is reliable in diagnosing adrenal tumors
False- can be elevated in Cushings but often normal with pheochromocytoma
What is a good screening test for Cushings *
Urine cortisol : creatinine ratio
very sensitive - so negative results rule it out
What are the diagnostic tests for Cushings *
1) Low-dose dexamethasone suppression test *
ACTH- stimulation test is not reliable
T/F: ACTH stimulation test is a reliable diagnostic test for Cushings
False
do low-dose dexamethasone suppression instead
What are the diagnostic tests for pheochromocytoma
1) Urine normatanephrine : creatinine ratio is most reliable
2) Plasma-free normetanephrine
Urine normatanephrine : creatinine ratio is most reliable diagnostic test for
pheochromocytoma
What do you do if LDDS test is negative and catecholamines are negative but you see an adrenal mass
-could be atypical Cushing
-could be non-functional
-could be false negative result
For an adrenal mass what should you do preoperatively
1) image the adrenal glands if not performed already
-Ultrasound
-CT
look for vascular invasion - particularly caval invasion
-this says there are more complications
2) Blood type for possible blood transfusion
3) Functional type has great impact on preoperative management
Is CT or ultrasound more sensitive for an adrenal mass
CT
Dogs with Hyperadrenocorticism are at risk for
______
______
______
during surgery ***
Infection
Thromboembolic disease
Dehiscence
Dogs with HAC are at risk for infection, how do you prevent when doing surgery
Administer perioperative antibiotics such as cefazolin
Dogs with HAC are at risk for thromboembolic disease, how do prevent this when doing surgery
Best anti-coagulant protocol is unknown (an controversial)
-Clopidogrel (Plavik)
-Heparin
-Enoxaprin, deltaparin (LMWH)
-Apixaban
*Stop a few days before going to surgery
Dogs with HAC, how do you replace steroids after removing the adrenal gland
Can use either dexamethasone or hydrocortisone (Dex is best)
this gives time for the other gland to increase
Prior to surgery, what do you give to dogs with pheochromocytoma so you are less worried about hypertension ***
1) Phenoxybenzamine (alpha-adrenergic antagonist)
0.5mg/kg orally daily for about 14 days preoperatively
The blood pressure should be monitored
2) B-adrenergic antagonist (ie Atenolol) the day of surgery if tachycardia is present
-B-adrenergic antagonist should not be used in the absence of phenoxybenzamine as it can trigger further release of catecholamines
In surgery with dogs with pheochromocytoma, what are you worried about
Hypertension
Phenoxybenzamine (alpha-adrenergic antagonist)
0.5mg/kg orally daily for about 14 days preoperatively
The blood pressure should be monitored
Prior to surgery for a dog with a pheochromocytoma, what should you give with a Beta-adrenergic antagonist (ie Atenolol) **-B-adrenergic antagonist should not be used in the absence of phenoxybenzamine as it can trigger further release of catecholamines
-B-adrenergic antagonist should not be used in the absence of phenoxybenzamine as it can trigger further release of catecholamines
What dog might increase the survival of dogs undergoing adrenalectomy for pheochromocytoma *
Phenoxybenzamine
however there is a newer study that did not find a difference
What approaches can you do for adrenalectomy
1) Ventral midline
2) Flank (not best, esp if there is caval invasion
3) Laparoscopy
What might be a better option for dogs with extensive tumor thrombus of the adrenal gland tumors
SRT
What should you monitor after adrenalectomy
1) Continue IV fluids
2) Proper analgesia - fentanyl CRI
3) Monitor Na+, K+, and glucose - dogs rarely require mineralocorticoid therapy after unilateral adrenalectomy
4) Bllod pressure
5) ACTH Stim
T/F: Dogs require mineralocorticoid therapy to maintain appropriate levels of Na +, K+, and glucose after unilateral adrenalectomy
False- they rarely do
What should you do the morning after adrenalectomy surgery ***
ACTH- stimulation test to see if you need to supplement with steroids
If surgery successful cortisol levels pre and post are below 1ug/dl
If levels elevated : surgery failed
If levels normal then surgery failed or wrong diagnosis (dont need steroid replacement therapy)
Morning after adrenalectomy, a dog with HAC has eleved ACTH stimulation test, then what occured
Surgery failure
Morning after adrenalectomy, a dog with HAC has normal ACTH-stumulation test.
What occured
surgery failed or wrong diagnosis
if levels normal or elevated, dont need steroid replacement therapy
Morning after adrenalectomy, a dog with HAC has low ACTH stimulation test. What occurred
if surgery successful = cortisol levels pre and post are below 1ug/dl
if levels are below 1ug/dl not a guarantee all will be fine
what are the prognostic factors of adrenal tumors
1) Size of tumor (large bad)
2) Invasion of vena cava: different results
3) Emergency surgery 50% mortality newer study
Diagnosis of adrenocortical adenocarcinoma vs pheochromocytoma are not diagnostic
Incidental adrenal gland lesion is found in
4% of dogs undergoing abdominal ultrasound and 9% undergoing CT
For incidental adrenal masses, what are always malignant
all lesions >2cm are malignant : recommend adrenalectomy
For incidental adrenal masses, if a lesion is <2cm what do you do
*
if <2cm and no clinical signs typical of adrenal tumor and no invasion then recommend careful monitoring
For incidental adrenal masses, if a lesion is >2cm, then what do you do? *
all lesions >2cm are malignant: recommend adrenalectomy
What percent of canine thyroid tumors are malignant
80-90% malignant (25-47% bilateral)
10-29% are functional and lead to hyperthyroidism
Where is the ectopic thyroid tissue that 13% of canine thyroid tumors arise from
Base of tongue
Ventral neck
Cranial mediastinum
Base of Heart
At initial canine thyroid tumor diagnosis _____ metastasis
40% metastasis
80% develop metastasis during course of disease
How do you diagnose canine thyroid tumors
1) Palpation: assess how freely movable
2) Imaging: ultrasound, CT, MRI
3) Cytology
4) Biopsy (rarely done)
What percent of canine thyroid tumors are functional
10-29%
What is the biological actively of canine thyroid tumors
can be highly vascular and invasive
-should be prepared to do blood transfusions
-should not be biopsied through keyhole incision
How do you stage canine thyroid tumors
-Chest, rads, CT
-CBC, chem, blood type or cross match
-FNA LNs - US guided for retropharynfeal
-Measure serum T4 concentration
-Perform laryngeal exam at induction
What are complications of thyroid surgery
1) Hemorrhage and anemia
2) Hypothyroidism (rare)
3) Laryngeal paralysis
4) Hypoparathyroidism (rare when unilateral)
5) Aspiration pneumonia
What are the prognostic factors of canine thy
1) Attachment or invasiveness into surrounding tissue
-Freely movable (3 years)
-Invasive (ST 6-12 months)
2) Size >20cm - negative
3) Histologic type- medullary thyroid carcinomas
many be a positive prognostic factor (less metastatic)
4) Vascular invasion
5) Bilateral tumors (controversial)- may be more likely to metastasize
How can you make the thyroid mass more visible
putting a pillow under the neck
What histological type of thyroid tumors may be a positive prognostic factor
medullary thyroid carcinomas
T/F: there is a better prognosis in thyroid tumors that are freely moveable
true (ST 3 years)
while invasive ones are 6 to 12 months
What is the use of radiation therapy for canine thyroid tumors
external bean
-thyroid tumors are responsive
Median survival time of 2 to 3 years
SRT for non-resectable tumors ~1 year
What kind of tissues can I131 treat
any throud tissue that concentrates I will be treated
-Orthotopic
-Ectpoic
-Metastatic
allows median survival 30months
but need 2-3 weeks of isolation
T/F: chemotherapy has huge response for canine thyroid tumors **
False- it has an unknown benefit
this is reserved for patients with negative prognostic facts
(typically do Doxorubicin, Carboplatin, mitoxantrone, pallaida)
What species is insulinomas most common in *
ferrets
functional tumor of beta cells of pancreas that secrete insulin *
Insulinomas
Are insulinomas more common in dogs or cats
Dogs occasionally get it
rare in cats
How do insulinomas behave in dogs *
vast majority are malignant and will metastasize
-liver
-lymph nodes
rarely get a cure for insulinomas in dogs
What is Whipple’s triad *
clinical signs associated with insulinomas
1) Hypoglycemia
2) Neuroglycopenic signs
3) Resolution of clinical signs with glucose supplementation
What are the 3 signs associated with insulinomas
1) Hypoglycemia
2) Neuroglycopenic signs
3) Resolution of clinical signs with glucose supplementation
What test can you use for insulomas
a paired insulin concentration is measured on serum in which hypoglycemis is documented
-insulin concentration above the norma range is diagnostic for insulinoma
-insulin concentration in the upper half of the normal range is highly suggestive of an insulinoma
-6% of dogs with an insulinoma have an insulin concentration in the lower half of the normal range
T/F: ultrasound is sensitive to insulinomas *
False - it is hard to diagnose on ultrasound
What is the best imaging technique to diagnose insulinomas
CT with triple phase
-portal
-arterial
-late phase
arterial lights up more
T/F: Pet CT with FDG works to diagnose insulinoma **
False
T/F: exploratory laparotyomy with methylene blue IV can help find insulinoma
False- and it has hemolytic anemia as a side effect
How do you treat insulinomas
emergency hypoglycemic event use IV dextrose
if dog hypoglycemic by stable then offer a small meal
long term medical management- frequent meals, prednisone, diazoxide, octreotide, Palladia, streptozocin
What is the treatment of choice for long-term control of insulinomas **
Surgery - may help for as minumum of 6 month
nodules are equally distributed between right and left limbs of pancreas
What may occur when doing surgical excision of pancreas
pancreatitis may occur from manipulating the pancreas
What do you need to monitor during surgical excision of the pancreas for insulinoma
glucose supplementation peri-op and constant monitoring on glucose intra-op
About ______ of dogs with insulinomas will have mets at the time of surgery
50%
How do you do surgical excision of pancreas for insulinoma
remove the nodules by partial pancreatecty
if you remove too much of the right limb, often have to combine with partial duodenectomy because of shared blood supply
if you remove too much of the right limb, you often have to
combine with partial duodenectomy because of shared blood supply
What are the two ducts of the exocrine pancreas
pancreatic duct and accessory pancreatic duct
-largest in dogs is the accessory pancreatic duct
there are communications between the ducts within the gland
What will happen if you have to sacrifice both the pancreatic duct and accessory pancreatic duct **
the dog will need to be treated for exocrine pancreatic insufficiency
After surgical removal of insulinoma, how do you treat postoperatively *
Treat as if they had pancreatitis: IV fluids, pain meds
Patient may have diabetes mellitus- may need insulin therapy lifelong or may be transient
After surgical removal of insuloma, what might the patient have *
Patient may have diabetes mellitus- may need insulin therapy lifelong or may be transient
