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45 Cards in this Set

  • Front
  • Back
How do pituitiary cysts form?
Develop from either:
Remnants of craniopharyngeal duct OR cystic dilation of the pituitary cleft.
What is the pathogenesis of Pituitary Juvenile (panhypopituitarism) Dwarfism?
Failure differentation cell of oropharyngeal ectoderm of Rathke's pouch to hormone-secreting cells of pars distalis --> cyst formation --> compression of other portions of pituitary --> panhypopituitarism
What breed does this most commonly affect? What are the gross lesions?
German Shepard Dog

Small in size, coyote appearnce to head --> long ears
What is the cause of suppurative inflammation in the pituitary gland.
Hematogenous spread of ruputred hepatic abscesses in cattle.
Describe the lesion associated with non-suppurative (lymphocytic) inflammation of the pituitary gland.
Extension of encephalitis into the neurohypophysis. Infiltration of lymphocytes and plasma cells.
What is the common neoplastic disease of the pituitary gland?
Corticotroph adenoma that may involve the pars intermedia or pars distalis in horses and dogs AND adenoma of the pars intermedia
What lesions are associated with corticotroph adenomas?
Pituitary mass and bilateral adrenal cortical hyperplasia.
What lesions are associated with adenoma of the pars intermedia in horses?
Usually large lesion that produces clinical syndrome of hirsutism, polyuria, polydypisa
What lesions are associated with adenoma of the pars intermedia in dogs?
Usually small and may be functionally inactive or produce Cushing's disease, diabetes insipidus or hypopituitarism.
What is diabetes inspidius?
Syndrome of polyuria and polydypsia from either lack of adequate ADH (hypophyseal form) or lack of renal response to hormone (nephrogenic form)
What lesions are assoicated with diabetes insipidus?
Pituitary neoplasms
Pituitary cysts
Post-traumatic hemorrhage
List two congential anomalies of the adrenal gland.
Accessory cortical nodules: extracapsular masses of cortical tissue that may become prominent with hyperplasia and mistaken for neoplasia.

Hypoplasia: seen with congenital pituitary aplasia.
What are 3 causes of adrenal cortical atrophy?
Hypopituitarism (lack of ACTH)
Exogenous corticosteroids (feed-back suppression)
Idiopathic in dogs (possibly immune-mediated)
What are the lesions of adrenal cortical atrophy?
Thin shell of cortex
Decreased size and weight
What are the causes of adrenal cortical hyperplasia?
ACTH-producing pitutiary chromophobe adenoma

Idiopathic hyperplasia (esp. poodles)
Describe the lesions of adrenal cortical hyperplasia.
Thick, yellow cortex
May be nodular
Increased size and weight
Proliferation of zona fasciculata
What are causes of adrenal cortical necrosis in dogs?

Adrenocorticolytic drugs --> selectively toxic for zona fasiculata and reticularis
What are the lesions of adrenal cortical necrosis in the dog?
Cortical necrosis, fibrosis and atrophy if chronic.

May produce Addison's Disease
List the causes of congestion and hemorrhage in the adrenal gland.
What can cause infarction of the adrenal glands?
Endothelial damage --> thrombosis caused by septicemia (Salmonellosis in horses) and toxemia (volvulus in horses)
Where are lesions of infarction localized in the adrenal gland?
Red wedge shaped lesion located in the cortex.
List and describe the three neoplasms found in the adrenal gland.
Cortical Adenoma: dogs and ferrets, encapsulated, expansive growth

Cortical Adenocarcinoma: Dog, ferret, cattle, occassionally functional (Cushings-like), invasive (Posterior VC, Aorta), metastasizes to liver and lung

Pheochromocytoma: Dog and bulls with C-cell tumors, slow growing, invasive and usually non-functional. Can metastisize to lung and liver
List two congenital anomolies of the thyroid gland.
Cysts (colloid filled)

Accessory glands (found anywhere between tongue and heart)
What are the 3 causes of thyroid atrophy?


Describe the lesion of thyroid atrophy?
Decreased size and weight, small amount of pale eosinophilic colloid, thin acinar epithilum, replacement by adipose tissue
List the three causes of thyroid hyperplasia.
Iodine deficiency
Deficient synthesis of hormone (consumption of goitrogens/genetic enzyme deficiency/Excess iodine)
Describe the pathogenesis of diffuse hyperplastic goiter.
Blocked or decreaed thryoxine --> excess TTH (TSH) production --> increased number of follicle cell pseudopodia and cells --> hyperplasia of follicle cells
Describe the gross and histologic lesions of diffuse hyperplastic goiter.
Gross: bilaterally enlarged, dark red, firm

Histo: tall follicle cells, little colloid, "resorption vacuoles" in colloid
Describe the pathogenesis of colloid "involutionary" goiter.
Deficiency of thryroid hormone --> increased TTH (TSH) --> follicle cell hyperplasia --> increased colloid and thyroid hormone --> decreased pitutiary TTH (TSH) --> decreased endocytosis of colloid by follicular cells with continued colloid synthesis and excess colloid accumulation --> BIG follicles
What are the gross and histologic lesions of colloid goiter?
Gross: bilaterally enlarged, translucent on section, light color

Histo: flattened follicular cells, abundant colloid, BIG follicles
What is the cause of lymphocytic thyroiditis in dogs?
Immune-mediated --> important cause of hypothyroidism
What are the lesions associated with lymphocytic thyroiditis in dogs?
Gross: pale, enlarged or atrophic

Histo: Extensive infiltrates of lymphocytes, plasma cells and macrophages --> replacement fibrosis eventually
List and describe the two most common neoplastic diseases of the thyroid gland.
Thyroid Adenoma: (1/3 of thryoid tumors) in dogs and horses --> well circumscribed mass, may cause hyperthyroidism in aged cats along with carcinoma or multinodular hyperplasia

Adenocarcinoma: (2/3 of cases) in dogs and horse --> extensive vascular invasion, only rarely functional
What clinical expressions of disease are assoicated with hyperparathyroidism?
Fibrous osteodystrophy

What are the clinical expression of disease with hypoparathyroidism?
Hypocalcemic tetany
What are the causes of parathyroid hyperplasia?
Primary idiopathic: functional parathyroid adenoma

Secondary to chronic renal disease (deficiency of renal 1-alpha-hydroxalase --> deficiency of Vitamin D3) OR (phosphate retention --> hyperphosphotemia --> decreased blood calcium levels)

Secondary to feeding high-phosphorus:low-calcium diets

Secondary to vitamin D deficiency

Tertiary to anal sac carcinoma or lymphosarcoma
What lesions are associated with hyperparathyroidsim?
Increased size and weight of glands, fibrous osteodystrophy in skeleton and soft tissue mineralization (metastatic)
What is the sequelae of hyperparathyroidism?

Metastatic mineralization
What is the common neoplastic disease of the parathyroid gland?
Parathyroid adenoma --> encapsulated mass that may be functional (hyperparathyroidism)
What are the causes of diabetes mellitus?
Idiopathic (dog, vacoulated islet cell)

Chemical Toxin (Alloxan, STH)

Chronic pancreatitis/pancreatic necrosis (dog)
What are the pancreatic lesions assoicated with diabetes mellitus?
Islet cell necrosis, amyloid deposits in islets, hyaline change in islets, chronic inflammation, atrophy and fibrosis of pancreas, ductal epithelium vacuolation from glygogen accumulation
What are extrapancreatic lesions assoicated with diabetes mellitus?
Fatty change in the liver and kidneys, glycogen accumulation in the liver and kidneys, cataracts, microangiopathy (kidney and retina)
What is the pathogenesis of diabetes mellitus?
Decreased insulin production --> glucose unable to enter some tissue --> hyperglycemia --> mobilization of fats for energy --> ketosis, acidosis --> coma
What is the pathogeneisis for diatebetes cataract formation?
Lens uses glucose via Kreb's cycle --> excess glucose --> shunts to sorbitol synthesis --> excess sorbitol increases lens osmotic pressure --> increased uptake of water --> hydropic degeneration and rupture of lens fibers --> cataract
What is the most common neoplastic disease of the endocrine pancreas?
Islet cell tumor "insulinoma" --> single or multiple gray firm masses that may be functional and produce hyperinsulinism and hypoglycemia (insulin shock)