Endocrine Pathology

Question 1

describe the pituitary gland

Answer 1

1. composed on pars nervosa, pars intermedia, and pars distalis
   -pars intermedia ad pars distalis have 3 cell types: acidophils, basophils, and chromophobes
2. if too big:
   -hyperplasia
   -adenoma
   -or carcinoma
   -of pars distalis or pars intermedia
3. produces lots of different hormones:
   -ACTH
   -prolactin
   -many others

Question 2

describe disorders of the pituitary gland and what results from these disorders

Answer 2

1. bilateral adrenal cortical hyperplasia: due to
   -pituitary corticotroph adenoma
   -in pars distalis or intermedia
   -primarily produce ACTH
2. pituitary lactotroph carcinoma (prolactinoma)
   -secretes prolactin and leads to mammary cell tumors
3. pituitary melanotroph adenoma:
   -in pars intermedia, produces pro-opiomelanocortin and leads to hirsuitism

Question 3

describe the adrenal gland

Answer 3

1. 2 parts that secrete 2 different hormones
   -disorders can make big or small
   -issues can begin with pituitary or with drugs (iatrogenic), or idiopathic
2. ddx for large cortex:
   -hyperplasia
   -adenoma
   -carcinoma
3. pheochromocytomas:
   -may be benign or malignant
   -tend to invade the vena cava which causes issues
4. ddx for small adrenals:
   -bilateral cortical atrophy
   -steroid therapy
   -pituitary stops producing ACTH
   -bilateral adrenal hemorrhage: waterhouse friderichson syndrome

Question 4

describe the thyroid glands

Answer 4

1. 2 parts:
   -follicular cells: produce thyroglobulin
   -C cells/interfollicular cells: produce calcitonin; regulate calcium by inhibiting osteoclasts
2. small:
   -atrophy: idiopathic or immune mediated
3. big: hyperplasia, adenoma, adenocarcinoma
   -congenital goiter: thyroid follicular hyperplasia due to too little or too much iodine

Question 5

describe thyroid nodular hyperplasia

Answer 5

1. old dogs, cats, horses
2. white to tan nodules of variable size and moderately enlarged
3. mostly inactive
   -except in CATS: usually functional

Question 6

describe unilateral thyroid adenoma

Answer 6

1. could be functional: hyperthyroidism
   -or nonfunctional
2. if hyperthyroidism, also see:
   -HCM
   -skin disease
   -weight loss

Question 7

describe thyroid carcinoma in dogs

Answer 7

1. most likely follicular adenocarcinoma but C cell carcinoma could also be called medullary thyroid carcinoma

Question 8

describe adult onset hypothyroidism in dogs

Answer 8

1. due to:
   -lymphocytic thyroiditis or
   -idiopathic follicular collapse
2. also see artherosclerosis and alopceia

Question 9

describe parathyroid hyperplasia

Answer 9

1. can be primary
2. or secondary due to:
   -nutritional or
   -renal

Question 10

describe the pancreas

Answer 10

1. endocrine and exocrine
2. islets secrete insulin, somatostatin, and glucagon
3. degenerative changes can cause diabetes and hyperglycemia
4. islet cell tumor:
   -insulinoma causes hypoglycemia
   -microscopically all islet cell tumors look alike! need immunohistochemistry to determine type

Question 11

describe the endocrine functions of the kidney

Answer 11

1. renin: regulate blood pressure
2. erythropoietin: stimulates RBC production
3. vitamin D: regulation of calcium levels