Endocrine Flashcards
In order from most common to least common, list the pathological processes of the endocrine system.
Disorders of growth Degeneration/necrosis Inflammation and repair Circulatory disorders and Deposits and pigmentations
Smoochie, a 6 year old MN Poodle comes into the clinic for hair loss, eating and drinking a lot, increased urinations, and general stank. You note that the alopecia is bilaterally symmetrical and that Smoochie has a pot belly. What hormone do you suspect is elevated?
Cortisol
*Cushing’s Disease
What are the primary and secondary mechanisms for Cushings disease?
Primary: Adrenal mass causing too much cortisol production from the adrenal cortex
Secondary: Pituitary mass releasing too much ACTH and overstimulating the adrenal cortex to produce cortisol.
Abdominal imaging on Smoochie shows an enlarged liver and one very enlarged adrenal gland with a possible mass. What kind of Cushing’s disease does Smoochie have?
Primary
The adrenal tumor is tan and greasy, but you see no gross metastasis. How can you determine for sure whether the mass is benign or malignant?
Send for histopathology
Smoochie’s adrenal tumor is sent to the lab. After looking at the histopathology, what would be your gross morphological diagnosis?
Adrenocortical adenocarcinoma
During your exploratory on Smoochie, you find that the liver is swollen and you decide to do a histology. Results show vacuolar hepatocellular degeneration. What is the likely cause of Smoochie’s liver disease?
Steroid hepatopathy of hyperadrenocorticism
*excess glycogen stores in the liver
Primary HA accounts for ____% of HA cases with half being benign tumors and half being malignant.
15%
T/F: Most adrenal tumors involved in primary HA are derived from the Zona Fasciculata.
TRUE
T/F: All adrenal tumors are productive and associated with hyperadrenocorticism.
FALSE
Secondary HA results from an ACTH producing pituitary tumor and accounts for ____% of HA cases.
85%
What part of the pituitary do most ACTH producing tumors arise from?
Pars distalis
T/F: Most pituitary tumors of the pars distalis are productive and benign.
TRUE
What are the effects of chronicly increased glucocorticoid levels on the body?
Epidermal and follicular atrophy
Hepatomegaly
Hypertension
Immunosuppression
Poor wound healing
Muscle strophy
PU/PD
What is a characteristic skin disorder associated with Cushing’s disease?
Calcinosis cutis
If this is a “functional” adrenal tumor, how does the other adrenal gland likely look?
Atrophied
The overproduction of cortisol from the diseased adrenal gland is sending negative feedback to the pituitary, so it stops producing ACTH and is no longer stimulating the healthy adrenal gland.
Another dog with clinical signs similar to Smoochie’s has bilaterally enlarged adrenal glands. What is the likely cause?
Pituitary adenoma on pars distalis producing ACTH
What is your morphological diagnosis for these adrenal glands?
MDx: adrenocortical hyperplasia
Due to pituitary adenoma
“Equine Cushings” or PPID, differs from canine Cushing’s by causing hirsuitism instead of alopecia, hyperhidrosis, and insulin resistance, and features normal cortisol levels. Why is this syndrome so different?
PPID horses have a NON-PRODUCING pituitary tumor that just squishes the hypothalamus. Signs are due to hypothalamus dysfunction.
In PPID, how do you expect the adrenal glands to look?
Normal. Adreals aren’t hyperplastic because there is no excess ACTH being produced.
Due to ADH deficiency, what is a major complication of Equine PPID?
Diabetes Insipidus
Unable to concentrate urine due to deficiency of ADH from the hypothalamus
What disorders would you expect to see in a animals with a persistent Rathkes pouch?
Dwarfism
Addisons
Hypothyroidism
*from hypopituitarism
A dog comes in with signs similar to Cushing’s disease, but cortisol is not elevated on the ACTH stim test, and adrenal glands are not located on abdominal imaging. The owner states that the dog has been healthy except for allergy flare-ups, which he received a depomedrol injection for. What would be your tenative diagnosis?
Addison’s disease
*Depomedrol injection caused iatrogenic Cushing’s disease, which lead to adrenocortical atrophy. Removal of the steroids induced Addison’s disease.
Which set of adrenal glands belong to a dog with Addison’s disease?
Top
Histology was submitted on the adrenal gland of a dog with suspected Addison’s disease. After examining the tissue, what hormones would you expect this dog to be deficient in?
Aldosterone AND Cortisol
Lymphocyte infiltration indicates that this is primary Addison’s disease, caused by immune-mediated lymphocytic adrenalitis, which wipes out the zona fasciculata as well as the zona glomerulosa.
Why can dogs with primary Addison’s disease have cardiac problems?
Aldosterone is responsible to reabsorption of N+ and excretion of K+. When aldosterone is lacking in promary Addison’s. there is an electrolyte imbalance, which affects heart contractions.
What are the causes of secondary Addison’s disease in dogs?
Idiopathic loss of stimulation from pituitary
Iatrogenic: long term steroids suddenly withdrawn
In which type of Addison’s disease is cortisol the only hormone deficiency?
Secondary
Removal of an adrenal gland in a dog with severe hypertension reveals a red colored tumor. What is the tumor and why was the blood pressure elevated?
Pheochromocytoma
Tumor of the adrenal medulla, which causes increased release of epi/norepi
Slinky the ferret comes in for an appointment because she has been drinking/peeing a lot, and has some hair loss. You note on exam that the alopecia is bilateral and that Slinky’s vulva is enlarged. Labs indicate that Slinky is anemic, and cortisol levels are normal. What is the likely cause of Slinky’s condition?
Hyperestrogenism due to gonadectomy at an early age.
Ferret adrenal neoplasm affects mostly adult, female ferrets that were spayed early in life. Loss of feedback inhibition leads LH to overstimulate the zona reticularis to make estrogen.
A farmer calls you to come check out his goats because 40 kids were either stillborn or died shortly after birth. Some are hairless, but all have swollen necks. What is the morphological diagnosis?
Thyroid hyperplasia
You send a sample of thyroid tissue from the dead goats for histo, which confirms thyroid hyperplasia, and indicates that the goats had hypothyroidism. How does the pathologist know?
Histo shows thyroid tissue with no colloid for thyroglobulin storage. Without colloid/thyroglobulin, no T4 can be synthesized.
You’re performing a necropsy on an overweight dog with bilateral alopecia and scaly skin. Upon examination of the heart, you find atherosclerosis of the coronary arteries. What disease could have caused this?
Hypothyroidism
Thyroid glands from a dog. What are the 2 mechanisms for this disease?
Lymphocytic thyroiditis (more common)
Idiopathic thyroid atrophy
*These thyroid glands are small. Hypothyroidism.
Histo from a dog’s thyroid glands. What is causing this dog’s hypothyroidism?
Lymphocytic thyroiditis
There is a marked infiltration of lymphocytes in the tissue. There is also a decrease in follicles, and basically no colloid, rendering the thyroid unable to synthesize T4.
Another histo from the thyroid glands of a dog. What is the cause of this dog’s hypothyroidism?
Idiopathic thyroid follicular atrophy
Why the long face?
This is cutaneous myxedema associated with hypothyroid disease in dogs. It is a result of mucin deposition in the tissue.
Thyroid glands in a cat with hyperthyroidism. What is your MDx?
Nodular thyroid hyperplasia
Histo of nodular thyroid hyperplasia in a cat. How worried are we about these nodules being malignant?
Not very. Less than 5% are carcinomas.
Most feline thyroid tumors are benign and productive.
What cardiac side effects can we see in cats with hyperthyroidism?
Hypertension
Tachycardia
Hypertrophy
Histo of thyroid gland from a dog. Is this likely to metastasize?
YES. 30% have already metastasized at the time of diagnosis. Thyroid carcinoma is very aggressive and carries a poor prognosis.
During a necropsy of a cat who died of cardiac complications from hyperthyroidism you find a small, dark spot on the tongue. What is this?
Ectopic thyroid tissue. Congenital malformation.
A 3 month old puppy recently died after being diagnosed with renal failure and hypercalcemia. You do a PM and find rubber jaw, fibrotic kidneys, and parathyroid glands that look like this… How do you know this dog didn’t die from parathyroid neoplasia?
The PT glands are symmetrically enlarged, which indicates hyperplasia rather than neoplasia.
It is more likely that the PT glands are enlarged secondary to renal failure. (Hypocalcemia of renal disease stimulates the PT gland to release PTH in order to raise blood Ca++ levels. Overstimulation will lead to hyperplasia.)
What kind of hyperparathyroidism will this lesion cause?
Primary
*Parathyroid adenoma
A dog comes in for surgery consult on an adenocarcinoma of the anal sac, a PTH-RP secreting neoplasm. What do you expect the parathyroid glands to look like in this case?
Smaller.
Anal sac carcinomas cause hypercalcemia of malignancy. Since blood Ca++ levels are already high, the PT glands are not stimulated.
What is the likely cause of fibrous osteodystrophy in this growing horse?
Nutritional hyperparathyroidism
High P, low Vit D, low Ca++ = inability to properly mineralize growing bone.
PTH stimulates bone resorption and bone marrow stromal cells differentiate into fibroblasts.
Giblets the dog dies suddenly after a brief history of neurological episodes and seizures. You find this nodule in the pancreas, and even though it doesn’t look like it’s spreading, you still to send it to the lab. What do you need to keep in mind for endocrine neoplasms when selecting a sample?
Sample the edges of the mass! Endocrine tumors have a low criteria of malignancy and can be mis-diagnosed as benign if the pathologist can’t clearly see the margins.
Surprise! You’re now the pathologist looking at Giblets’ pancreatic nodule (left). What is your morphological diagnosis?
Pancreatic islet cell carcinoma
Packets of cuboidal cells in the endocrine pancreas
A histo of Giblets’ brain tissue shows neuronal necrosis. This explains the seizures, but what could have caused the necrosis in the first place?
Hypoglycemia
*Giblets has an insulin-producing Beta cell tumor
Acute and chronic pancreatitis in a dog. How can this lead to diabetes mellitus?
Destruction of the endocrine pancreas and Beta cells that produce insulin will result in hyperglycemia.
Pancreas of an obese diabetic cat. What is causing the vacuolar degeneration of the Beta cells?
Long term intracellular accumulation of glycogen within the Beta cells.
Leads to insulin deficiency
Histo of a pancreas from a diabetic cat. Long term overstimulation of Beta cells is causing:
Pancreatic amyloidosis
Leads to crowding and atrophy of islet cells
Kidney from a diabetic dog, illustrating diabetic nephropathy. Deposition of glycosylated proteins into capillary basement membranes predisposes the kidney to:
Ischemia and renal failure
