Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Endocrine > Thyroid Pathology > Flashcards

Thyroid Pathology Flashcards

(45 cards)

Start Studying
1
Q

Normal embryological development

A

Develops from evagination of pharyngeal epithelium

Descent from foramen caecum to normal location in anterior neck below larynx along thyroglossal duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Embryological Abnormalities

A

Failure of descent
–> lingual thyroid

Excessive descent
–> retrosternal location in mediastinum

Thyroglossal duct cyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Thyroid composition

A

Composed of lobules defined by thin fibrous septa each containing follicles
Each follicle surrounded by flat to cuboidal follicular epithelial cells
Within centre each each follicle is dense amorphous pink material containing thyroglobulin
Occasionally scattered C cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

C cells

A

parafollicular cells
Slightly larger cells with clearer cytoplasm
Secrete calcitonin
Results in lower serum Ca levels (little clinical significance)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Thyroid Function: BMR

A

Increases basal metabolic rate

Hypothalamus produces TRH
TRH stimulates anterior pituitary to release TSH
TSH binds to TSH receptor on surface of thyroid epithelial cells.
G-proteins activated with conversion of GTP to GDP and production of cAMP
cAMP increases production and release of T3 and T4
T3 and T4 circulate in free and bound forms

On release T3 and T4 bind to receptor in target cells

  • complex translocates to nucleus
  • binds to thyroid response elements on target genes
  • stimulates transcription of genes
  • -> increases BMR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Thyroiditis

A

Inflammation of the thyroid gland

Acute: bacterial infection
Subacute (de Quervain’s): Viral infection
Chronic: abnormal immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thyroiditis Autoimmune Disease

A

Hypofunction: Hashimotos Thyroiditis

Hyperfunction: Graves Disease

Susceptibility associated with HLA calotype

Polymorphisms in immune regulation associated genes

  • CTLA-4
  • PTPN-22
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Thyrotoxicosis

A

Syndrome occurs as a result of excess T3 and T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

hyperthyroidism aetiology

A 
Graves disease
hyper functioning nodules and tumours 
TSH secreting pituitary adenoma 
Thyroiditis 
Ectopic production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Graves Disease

A

Autoimmune Disorder
- hyperthyroidism

Autoantibodies to TSH receptor, thyroid peroxisomes and thyroglobulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Anti-TSH receptor autoantibodies (seen in Graves)

A

Thyroid stimulating immunoglobulin
Thyroid growth stimulating Immunoglobulin
TSH binding inhibitor immunoglobulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Graves Disease features

A

Hyperthyroidism with diffuse enlargement of the thyroid

Eye changes (exophthalmos) 
- results from fibroblasts expressive TSH receptor

Pretibial Myxoedemaa

Follicles contain little or no thyroglobulin

Abundance of lymphoid follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Hypothyroidism

A

Symptoms and signs due to low levels of T3 and t4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

hypothyroidism aetiology

A 
hashimotos thyroiditis (most common cause) 
iodine deficiency
drugs (lithium)
post therapy
congenital abnormalities

Rare

  • Secondary (pituitary) pathology
  • tertiary (hypothalamic) pathology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hashimoto Thyroiditis

A

Gradual failure of thyroid function

Autoimmune destruction of thyroid tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hashimotos Thyroiditis Epidemiology

A

Affects middle aged women
Associated with other autoimmune disease
HLA-DR3 and DR5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Anti-thyroid antibodies (hashimotos thyroiditis)

A

Anti-thyroglobulin and anti-peroxidase

When bound cause antibody dependent cell mediated cytotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hashimotos Thyroiditis Pathophysiology

A

Antibody dependent cell cytoxicity due to anti-thyroglobulin and anti-peroxidase

CD8+ve cells mediate destruction of thyroid epithelium

Cytokin mediated cell death
- gama interferon from T cell activation recruits macrophages that may damage thyroid follicles

Thyroid may be diffusely enlarged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Hashimotos Thyroiditis: Histology and Follicles

Study These Flashcards
A

Prominent lymphoid infiltrate

  • lymphocytes
  • plasma cells
  • reactive follicles with germinal centres

Thyroid follicles atrophy

  • follicular cells have abundant eosinophilic cytoplasm
  • -> Hurthle cells

may see progressive fibrosis within gland

20
Q

hashitoxicosis

Study These Flashcards
A

Transient hyper function of gland

can precede progressive fibrosis within gland

21
Q

Hashimotos Thyroiditis risks

Study These Flashcards
A

Increased risk of other autoimmune disease

Increased risk of developing B cell NHL in affected glands

22
Q

Goitre

Study These Flashcards
A

Enlargement of thyroid gland

Reduced t3/T4 production causes rise in TSH, stimulating gland enlargement

23
Q

Diffuse goitre

Study These Flashcards
A

T3/T4 normal
TSH elevated

usually euthyroid- present with mass effects

Sporadic

  • F>M
  • Puberty and young adults
24
Q

multi-nodular goitre

Study These Flashcards
A

Evolution from long-standing simple goitre
- recurrent hyperplasia and involution

Variation of response of follicular cells to external stimuli
-mutations of TSH signalling pathway

Ruptures of follicles, haemorrhage, scaring and calcification

Mass Effects: Cosmetics, airway obstruction, dysphagia, compress vessels

May develop autonomous nodule
-hyperthyroid (low risk of malignancy <5%)

25
neoplasms
Adenomas - follicular adenoma carcinoma - papillary - follicular - medullary - anaplastic
26
Adenomas
Discrete solitary mass Encapsulated by a surrounding collagen cuff Composed of neoplastic thyroid follicles --> follicular adenoma Can be difficult to distinguish from - dominant nodule in MNG - follicular carcinoma
27
Adenomas- function
Usually non-functional Can secreted thyroid hormone - thyrotoxicosis - -> TSH independent Functional -Thyroid adenoma
28
Thyroid Adenomas
Mutations of TSHR signalling pathway in functional adenomas Activating - TSHR - G-proteins Increase cAMP levels
29
Carcinomas epidemiology
Can affect any age group | - female predominance
30
Thyroid malignancy
Most are well differentiated and derived from follicular epithelium (Medullary from C cells) Carcinomas - Papillary - Follicular - Medullary - Anaplastic
31
Carcinoma Aetiology (Environment Associations)
Ionising Radiation - Papillary carcinoma Iodine Deficiency - follicular carcinoma
32
Carcinoma Aetiology (genetic Features)
Papillary: Activate MAP kinase pathway - Rearrangements of RET or NTKR1 - Activating point mutation in BRAF - Mutation of RAS Follicular - Mutations in P13k/ AKT pathway - Mutation in ras family - translocation involving Pax8 and PPAR-gamma-1 Anaplastic - features of. above types - p53 and B-catenin medullary -MEN2
33
Papillary carcinomas
Most common type of thyroid cancer Usually solitary nodule - can be multifocal - often cystic - may be calcified: psammoma bodies Sometimes present with lymph node metastasis
34
Papillary carcinoma presentation
Lesion in thyroid gland or cervical lymph node mass Local effects - hoarseness - dysphagia - cough - dysponoea haematogenous spread is uncommon - usually to lungs Overall good survival rates
35
Follicular carcinoma epidemiology
Females> Males Older than with papillary (40s and 50s0)
36
Follicular Carcinoma Presentation
Usually single nodule - slowly enlarging, painless and non-functional Rare lymphatic spread Propensity from haematogenous spread -bones, lungs, liver invasive growth pattern
37
Follicular Carcinoma Prognosis
Depends on extent of invasion and stage of presentation High stage at presentation -50% mortality art 10 years Minimally invasive lesions - >90% survival at 10 years
38
Medullary Thyroid Carcinoma
Relatively rare Derived from C-cells (neuroendocrine) - secrete calcitonin
39
Medullary thyroid carcinoma aetiology
Sporadic: solitary nodule Associated with Men IIA or IIB Familial medullary carcinoma Familial cases: bilateral or multi centric - C-cell hyperplasia
40
Medullary thyroid carcinoma composition
Composed of spindle or polygonal cells arranged in nests, trabecular or follicles
41
Medullary Thyroid Carcinoma Associations
Associated amyloid deposition | Amyloid represents deposition of abnormally folded protein: calcitonin
42
Medullary Thyroid Carcinoma presentation
neck mass with local effects - dysphagia - hoarseness - airway compromise paraneoplastic Syndrome - diarrhoea (VIP production) - Cushings (ACTH production0
43
medullary thyroid carcinoma mangement
Total thyroidectomy Local recurrence in 35% Good prognostic factors - young age, female - tumour size, confined to thyroid, no. mets MENIIB has more aggressive potential
44
Anaplastic Carcinoma
Undifferentiated and aggressive tumours
45
Anaplastic Carcinoma Presentation
Usually older patients may occur in people with a history of differentiated thyroid cancer Rapid growth and involvement of neck structures and death

Endocrine (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions