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Flashcards in Thyroid pathology Deck (37)
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1

Why are biopsies not usually performed on the thyroid gland?

What is the alternative?

Thyroid gland is very vascular

Do FNA instead

2

Describe the normal appearance of the thyroid gland?

Fleshy, mahogany coloured

3

Describe the origin of the cells of the thyroid gland?

C cells are neuroendocrine in origin

Rest are of epithelial origin

4

Describe the normal histology of the thyroid gland?

Round/oval follicles, various sizes

Epithelial cells line follicles 

Follicles filled with colloid 

Thin, fibrous septa with rich vascular supply 

C cells (difficult to distinguish in H&E)

5

Describe the different histological appearance of inactive and active thyroid follicles?

Inactive: low cuboidal cells, follicle filled with colloid

Active: tall cuboidal/columnar cells, scalloping of colloid (cells taking up colloid)

6

Describe the metabolic symptoms of hypothyroidism?

Hypometabolic state:

cold intolerance

alopecia

cold, thickened skin

weight gain

fatigue

 

7

Describe the effects of hypothyroidism on the nervous system and the consequences of this?

Sympathetic nervous system underactivity > bradycardia, angina, slow reflexes, constipation, decreased mood and concentration 

8

Which population is most affected by hypothyroidism?

Children

9

What are the most common causes of hypothyroidism?

Iodine deficiency

Hashimoto's disease

10

What is thyrotoxicosis?

Elevated circulating fT3 and fT4

Includes hyperthyroidism

11

Describe the metabolic effects of hyperthyroidism?

Hypermetabolic state:

heat intolerance

warm, flushed skin

fatigue

weight loss

osteoporosis

12

Describe the effects of hyperthyroidism on the nervous system, and the consequences of this?

Sympathetic nervous system overactivity > palpitations, AF, cardiomegaly, tremor, anxiety, insomnia, diarrhoea

13

What are the major causes of thyrotoxicosis?

Graves disease

Hyperfunctioning toxic multinodular goiter

14

Describe the cause of a simple goiter?

Impaired synthesis of thyroid hormone > TSH elevation > thyroid growth stimulated 

15

Describe the thyroid hormone levels in a simple goiter?

Usually euthyroid, with slightly high TSH 

16

What is the most common cause of simple goiter?

Iodine deficiency

17

Describe the histological appearrance of a simple goiter?

Hyperplasia

Crowded cells line follicles

Some follicles largr than others

Large colloid-filled cysts may be present

 

18

Describe what happens to the thyroid follicles in a simple goiter with:

a) TSH resolution

b) TSH persistence

a) Follicles incolute 

b) Follicles rupture, haemorrhage or grow larger

19

Describe what can happen to a simple goiter over time?

Cycles of hyperplasia and involution > follicles can become large nodules > multinodular goiter

20

What can multinodular goiter progress to?

What are the consequences of this?

Nodules can be autonomous (secrete thyroid hormone without TSH) > toxic multinodular goiter

Patient may become hyperhtyroid 

21

What is Pemberton's sign?

When does it occur?

Enlarged thyroid > compresses SVC when arms raised > blood backlog in SVC 

22

Describe the histological appearrance of Hashimoto's thyroiditis?

Mononuclear inflammatory infiltrate: lymphocytes, plasma cells, germinal centres

Hurthle cells: thyroid cells with abundant, eosinophilic, granular cytoplasm

Increased interstitial connective tissue: fibrosis/scarring 

 

23

Describe the gross pathology of Hashimoto's thyroiditis?

Enlatge at first > atrophic 

Cut surface: firm, tan-yellow, pale, nodular 

24

Describe the cause of Hashimoto's thyroiditis?

Breakdown of tolerance to thyroid tissues

Damage by: CD8 cytotoxic cell-mediated death, cytokine-mediated cell death, TSH-blocking Abs

25

Which population is most affected by Hashimoto's thyroiditis?

Females

45-65 yo

26

Describe the clinical presentation of Hashimoto's thyroiditis?

Hypothyroidism

Goiter

High Anti-g Abs

Very high Anti-TPO

High TSH, low fT4

27

Describe the triad of clinical findings in Graves disease?

1) Hyperhtyroidism due to diffuse, hyperfunctional enlargement of the thyroid

2) Infiltrative opthalmopathy > exopthalmos

3) Localised infiltrative dermopathy (pretibial myxoedoma)

28

What is the cause of Graves disease?

Stimulatory auto-Ab to TSH receptor 

29

Describe the histological appearance of Graves disease?

Tall, crowded follicular cells > papillae

Diffuse hypertrophy and hyperplasia 

Widespread scalloping

Lymphocytic infiltrates 

30

Describe the gross pathology of Graves disease?

Diffuse symmetrical enlargement of thyroid

Soft, meaty cut surface