thyroid Gland Disorders 4

Question 1

what is Solitary thyroid nodule (STN)?

Answer 1

Refers to a palpable, discrete swelling (usually >1cm) within an otherwise normal thyroid gland

Question 2

solitary thyroid nodules can be of 2 types?

Answer 2

Neoplastic: benign or malignant

Non neoplastic: goiter, colloid filled cyst etc

Question 3

when is Solitary thyroid nodule usually malignant?

Answer 3

In men and children

Question 4

soiltary thyroid Nodules that take up radioactive iodine (hot nodules)*** are more likely to be what?

Answer 4

benign

Question 5

what investigations can be done for solitary thyroid nodules?

Answer 5

1. Thyroid ultrasound to determine size
2. Thyroid function tests (TSH)
3. Thyroid scan only if TSH is low to determine if nodule is hot
4. Significant 131I uptake into nodule which signifies very low malignant potential
5. FNA for all nodules >1-1.5 cm, if not hot nodule

Question 6

what are the benign tumors of the thyroid?

what are adenomas?

what can they cause?

Answer 6

adenomas

discrete , solitary masses. Most derived from follicular epithelium.

thyrotoxicosis because some may produce thyroid hormone

Question 7

what are the different types of adenomas?

Answer 7

Follicular adenomas

Hurthle cell adenoma

Question 8

what can be said about follicular adenomas?

Answer 8

• Composed of follicles
• Surrounded by a complete capsule

Question 9

what is the clinical presentation of a thyroid adenoma?

Answer 9

• Usually present as painless mass.
• Must be differentiated from a carcinoma.
• Most are cold on thyroid scan.
• Some are hot (toxic adenoma)

Question 10

Malignant thyroid tumors have these common general characteristics?

Answer 10

• Present as a palpable mass
• Most are cold nodule on thyroid scan

Question 11

Factors that suggest malignancy of the thyroid?

Answer 11

• History of irradiation to head and neck.
• Solitary nodule in man or child
• Irregular nodule with cervical lymphadenopathy.

Question 12

what are the subtypes of thyroid carcinomas?

Answer 12

• Papillary carcinomas******
• Follicular carcinoma
• Medullary carcinoma***
• Anaplastic carcinoma.

Question 13

Most cancers arise from what epithelium?

except for which one?

Answer 13

follicular epithelium

Medullary (arises from C cells).

Question 14

papillary carcinoma is related to what activity?

what are the gross findings?

Answer 14

radiation exposure

• Usually Multifocal
• Often cystic.
• Cut section: papillary fronds.

Question 15

what are the micro findings in papillary carcinoma?

Answer 15

• Branching papillae lined by cuboidal cells.
• Nuclear features:
  
  • Empty appearing nuclei
    
    • Called Orphan Annie eye nuclei
    • optically clear or empty appearance due to finely granular and dispersed chromatin.
  • Intranuclear grooves
• Psammoma bodies :
  
  • dystrophically calcified cancer cells.

Question 16

papillary carcinoma metastasizes via what?

Answer 16

lymph nodes

Question 17

what areas have a higher incidence of follicular carcinoma?

Answer 17

Higher incidence in iodine deficient areas.

Question 18

what are the gross findings in follicular carcioma?

Answer 18

1. Composed of neoplastic follicles lined by malignant cells and containing colloid.
2. Follicles invade blood vessels and capsule:

• Capsular or blood vessel invasion helps to distinguish follicular carcinoma from follicular adenoma
• FNAC only examines cells and not the capsule– hence the distinction can not be made by FNAC

3. No psammoma bodies or nuclear features of Papillary carcinoma.

Question 19

how does follicular carcinoma spread?

Answer 19

blood - more likely distat (lungs is common)

Question 20

what genes are related to medullary carcinoma?

what type of protein do you see?

what may it secrete?

Answer 20

MEN IIa, IIb- RET proto-oncogene

amyloid

May secrete calcitonin, PG, ACTH, serotonin

Question 21

familial medullary carcinoma of the thyroid is related to MEN 2a, and this is also related to what other diseases?

Answer 21

• hyperparathyroidism
• pheochromocytoma

Question 22

familial medullary carcinoma of the thyroid is related to MEN 2b, and this is also related to what other diseases?

Answer 22

pheochromocytoma, mucosal neuromas (lips/tongue) and marfanoid features.

Question 23

Medullary Carcinoma of Thyroid arises from where?

Answer 23

C cells of the thyroid

Question 24

C cells of the thyroid synthesize what?

this works as what?

(what they make) this can be converted to what? and what happens to that?

C cell hyperplasia is a what?

Answer 24

calcitonin

a tumor marker

amyloid- gets deposited in tumor

precursor lesion

Question 25

what mutation can you test for if you are looking for familial medullary carcinoma of the thyroid?

if positive, what can you do?

Answer 25

RET protooncogene

do a prophylactic thyroidectomy

Question 26

what hormone can familial medullary carcinoma of the thyroid produce?

what can it lead to?

Answer 26

ACTH

Cushing’s syndrome

Question 27

what are the micro findings of medullary carcinoma of the thyroid?

Answer 27

• composed of neoplastic C cells.
• Amyloid deposits (derived from calcitonin) in the tumor.

Question 28

metastasis of medullary carcinoma of the thyroid is common through what medium?

Answer 28

blood to distant sites

Question 29

what are the gross findings of medullary carcinoma of the thyroid?

Answer 29

present as nodules , usually Solitary in sporadic type and multiple in familial type.

Question 30

what is this?

Answer 30

anaplastic carcinoma

Question 31

what is this?

Answer 31

anaplastic carcioma

Question 32

what is Anaplastic Carcinoma?

how fatal is this?

Answer 32

Rapidly growing tumor that often invades local structures leading to dysphagia or respiratory compromise

very fatal due to rapidly growing nature