Pathology of The Endocrine System

Question 1

How is balance in the endocrine system maintained?

Answer 1

Feedback inhibition

Question 2

What is included in the endocrine system?

Answer 2

Pineal gland, hypothalamus, hypothalamus, pituitary gland, thyroid gland, parathyroid gland, adrenal glands, pancreas
Also ovary, testes and kidneys

Question 3

What are some disease processes in endocrine organs?

Answer 3

Hyperplasia
Atrophy
Tissue damage
Neoplasia
Congenital abnormality

Question 4

What is the differences between benign and malignant neoplasia?

Answer 4

Benign - often circumscribed, localised, cant invade and don’t usually transform
Malignant - cancer, invades, metastasises, and can be fatal

Question 5

What are some important aspects of endocrine diseases?

Answer 5

Endocrine organs have high reserve capacity
Feedback effects may cause endocrine changes
Can have multiorgan effects

Question 6

Describe the anterior pituitary

Answer 6

Adenohypophysis
Secretes ACTH, TSH, GH, prolactin, FSH/LH
Blood supply from hypothalamus
Controlled by release factors from hypothalamus

Question 7

Describe the posterior pituitary

Answer 7

Neurohypophysis
Downgrowth of hypothalamus
Secretes ADH and Oxytocin

Question 8

What is the most common cause for pituitary hyperfunction?

Answer 8

Pituitary adenoma

Question 9

Describe a pituitary adenoma

Answer 9

Usually adults - 35-60years
Most sporadic - 5% inherited
Macroscopic - soft, well circumscribed and mainly an incidental finding

Question 10

What are the effects pituitary adenoma?

Answer 10

If functioning then hormone excess
Prolactinoma, GH secreting and ACTH secreting (Cushing’s)
Non functioning

Question 11

What large pressure effects can an pituitary adenoma give?

Answer 11

Radiograhic abnormalities
Visual field abnormalities
Elevated intracranial pressure
Compression damage - hypopituitarism

Question 12

What is pituitary hypofunction?

Answer 12

75% needs to be lost
Can be compression by tumours
Trauma, infection, TB or sarcoidosis
Sheehan’s syndrome - post partum ischaemic necrosis

Question 13

Describe the histology of thyroid gland

Answer 13

Follicles
Colloids containing thyroglobulin
Epithelial cells - TG synthesis, iodination resorption and release of T3/4
C cells - secrete calcitonin

Question 14

What are manifestation of thyroid disease?

Answer 14

Hyperthyroidism - thyrotoxicosis
Hypothyroidism - myxoedema, cretinism, subclinical
Enlargement - goitre and isolated mass/ nodule

Question 15

What are the causes of hyperthyroidism?

Answer 15

Graves disease - diffuse toxic hyperplasia
Toxic multinodular goitre
Toxic adenoma

Question 16

Describe Graves disease

Answer 16

Autoimmune production of anti-TSH receptor antibodies
Stimulate growth, activity and inhibit TSH binding
More females - peak 20-40yrs
Genetic predisposition
Hyperplasia and hyperfunction

Question 17

What is the histology for Graves disease?

Answer 17

Increased cell activity and cell numbers
Scalloping of colloids

Question 18

What are some causes of hypothyroidism?

Answer 18

Hashimoto’s thyroiditis
Iatrogenic - surgery and drugs
Iodine deficiency
Congenital hypothyroidism

Question 19

Describe Hashimoto’s thyroiditis

Answer 19

Autoimmune destruction of thyroid epithelial cells
More females - 45-65 yrs
Cytotoxic T cells, cytokine and antibody mediated destruction
Circulating autoantibodies to thyroglobulin and thyroid peroxidase

Question 20

What happens to the thyroid gland in Hashimoto’s thyroiditis?

Answer 20

Diffuse enlargement gradual failure

Question 21

Describe the histology of Hashimoto’s thyroiditis

Answer 21

Hurthle cell change - ore pink and rounded (more cytoplasm)
Intense infiltration of lymphocytes and plasma cells

Question 22

Describe the process of formation of multinodular goitre

Answer 22

Iodine deficiency and goitrogens - impaired synthesis of T3 and T4 - increased TSH - hypertrophy and hyperplasia of epithelium
Then simple to multinodular

Question 23

Describe the histology of multinodular goitre

Answer 23

Crowded follicles
Distended colloid filled follicles
Haemorrhage, fibrosis and cystic change
Nodular appearance

Question 24

What can a thyroid nodule be?

Answer 24

Dominant nodule in multinodular goitre
Cyst
Follicular adenoma
Carcinoma - differentiated - papillary, medullary, follicular and anaplastic

Question 25

What are the investigations for thyroid nodules?

Answer 25

TFTs US FNA - cytology

Question 26

What are the risk factors for thyroid carcinoma?

Answer 26

FH, chronic inflammatory disease, radiation exposure and obesity

Question 27

Describe follicular adenoma

Answer 27

Mostly non-functioning Circumscribes and encapsulated Histology - small micro-follicles

Question 28

Describe follicular carcinoma

Answer 28

Rare and usually solitary Malignant cells breach capsule Metastases - blood and bones RAS mutation or PAX8/PPARG translocation

Question 29

Describe papillary carcinoma

Answer 29

Usually over 50 yrs BRAF mutation or RET/PTC gene rearrangement Spreads via lymphatics but good prognosis Associated with ionising radiation

Question 30

What is the histology of papillary carcinoma?

Answer 30

Papillary projections, empty nuclei, psammoma bodies and may be cystic

Question 31

Describe medullary carcinoma

Answer 31

Malignant tumour of c cells Produces calcitonin 70% sporadic Some MEN2a, b and familial FMTC - mutations in RET proto-oncogene

Question 32

What is the histology of medullary carcinoma?

Answer 32

Tumour cells Amyloids

Question 33

What is the treatment for thyroid carcinoma?

Answer 33

Surgery, radio-active iodine, external radiotherapy and chemo

Question 34

What is primary hyperparathyroidism?

Answer 34

Often asymptomatic hypercalcaemia Sporadic or familial (MEN1) Adenoma mainly, hyperplasia or carcinoma (rare)

Question 35

What is secondary hyperparathyroidism?

Answer 35

Physiological response to decreased Ca renal failure As feedback loop so increases PTH

Question 36

What are multiple endocrine neoplasia (MEN)?

Answer 36

Inherited disorders with underlying genetic mutation Hyperplasia/ neoplasms of endocrine organs - younger age and multifocal Autosomal dominant

Question 37

Describe MEN1

Answer 37

MEN1 tumour suppressor gene mutation - defect in menin protein involved in regulating cell growth

Question 38

What is affected in MEN1?

Answer 38

Parathyroid hyperplasia and adenomas Pancreatic (hypoglycaemia) and duodenal (ulcers) endocrine tumours Pituitary adenoma

Question 39

Describe MEN2

Answer 39

RET proto-oncogene mutation Medullary carcinoma of thyroid Pheochromocytoma

Question 40

What is involved in MEN2A?

Answer 40

Sipple syndrome Parathyroid hyperplasia Extracellular domain auto-dimerization of RET receptor

Question 41

What is involved in MEN2B?

Answer 41

Neuromas of skin and mucous membrane Skeletal abnormalities Younger patients and aggressive Autoactivation of tyrosine kinase pathway