Thyroid - Thyroid Nodules and Thyroid Cancer Flashcards
Are thyroid nodules mostly benign or malignant?
Benign
What two features are suggestive of the nodule being within the thyroid?
- It moves on swallowing
- It is painless
If a nodule is in the thyroid, what type of fascia will it be invested in?
Pretrachial fascia
When will a thyroid nodule be painful?
If a cyst has formed which is bleeding and expanding
What are the two most important questions in a history of a thyroid nodule?
- Has there been neck irradiation?
- Is there a family history of thyroid cancer?
What are two important things to look/assess for on examination of a thyroid nodule?
- Lymphadenopathy in the neck
- Hoarseness of the voice
If lymph nodes are found in the neck along with a thyroid nodule, what is this until proven otherwise?
Papillary thyroid cancer
What is hoarseness of the voice suggestive of?
Recurrent laryngeal nerve palsy- an aggressive cancer
What are the most important investigations for a thyroid nodule?
- TSH levels
- US and FNA
What are the different FNA/US stages and what does each signify?
Thy1- inadequate Thy2/U2- benign Thy3 (a/f)/U3- atypical Thy4/U4- probably malignant Thy5/U5- malignant
Thy3a FNA staging has what % chance of being malignant?
30%
Where do most thyroid tumours arise from?
Follicular cells
What is the most common tumour of the thyroid?
Follicular adenoma
What type of tumours are follicular adenomas?
Benign, glandular
Follicular adenomas are encapsulated. What does this mean?
They are surrounded by a band of collagen within which there are closely packed thyroid follicles
Are follicular adenomas functioning or non-functioning?
Normally non-functioning but can sometimes secrete thyroid hormones
If a follicular adenoma was to secrete thyroid hormones, is this TSH dependent or independent?
TSH independent
What genetic mutations are associated with follicular adenoma?
Ras oncogene
TSHR signalling pathway
As well as follicular adenoma, what are some other causes of a benign solitary nodule?
- Cyst
- Colloid nodules
- Hyperplastic nodules
Most thyroid cancers are what type?
Carcinomas
What are carcinomas?
Malignant epithelial tissue
Which types of thyroid carcinomas can be differentiated?
Papillary and follicular
What thyroid carcinoma is the most common?
Papillary
What does it mean for a cancer to be differentiated?
They look and behave very similarly to normal cells
What is the main advantage and main disadvantage of differentiated cancer?
D: can be hard to spot/diagnose
A: very good prognosis
Most differentiated cancers take up X, secrete Y and are Z driven?
X= iodine Y= thyroglobulin Z= TSH
Which sex is more commonly affected by thyroid cancers?
Females
How do the rates of thyroid cancer vary with age in both men and women?
Women- rates increase from age 15-40 and then plateau
Men- rate steadily increases with age
Thyroid cancers have a lower incidence in what race?
Afro-Americans
Thyroid cancers have a strong association with what environmental factor?
Exposure to radiation
How soon after a nuclear incident do effects start to show?
Exactly 25 years
What 3 things does thyroid cancer have a weak association with?
- Thyroid adenoma
- Chronic elevation of TSH
- More children a woman has had
What factors does thyroid cancer have NO association with, that are common risk factors for other cancers?
Diet, other malignancies, smoking
What do most thyroid cancer patients present with?
A palpable nodule, most likely to be an enlarged lymph node