thyroid 4

Question 1

most thyroid neoplasms present as

Answer 1

solitary nodules as incidental findings

ddx is between colloid nodule, adenoma and carcinoma

Question 2

most thyroid neoplasms

Answer 2

non functional - don’t produce hormones
less than 1% of solitary thyroid nodules are malignant - still many cases because they’re common
most thyroid cancers are indolent - low stage follicular and papillary - 90% 20 year survival

Question 3

clues to the nature of a thyroid nodule

Answer 3

• solitary are more likely neoplastic
• nodules in younger patients more likely neoplastic, but more likely better prognosis
• nodules in males more neoplastic
• radiation exposure history more neoplastic
• nodules taking up radioactive iodine more likely benign than malignant

Question 4

nodules that take up radioactive iodine

Answer 4

hot nodules

more likely to be benign than malignant

Question 5

history of radiation exposure is associated with

Answer 5

increased incidence of thyroid malignant

Question 6

adenomas

Answer 6

benign epithelial tumours

follicular adenoma
hurthle cell adenoma

Question 7

carcinomas

Answer 7

malignant epithelial tumours

follicular
papillary - common
anaplastic - undifferentiated
medullary - nueroendocrine - carcinoma

Question 8

adenoma

Answer 8

• most are follicular, hurthle cell less common
• solitary nodule
• well circumscribed
• encapsulated
• usually normal background thyroid
• important - no capsular invasion, extra thyroidal extension or lymph-vascular invasion
• usually non functional, euthyroid
• may cause hyperthyroidism
• treatment is hemithyroidectomy

Question 9

adenoma nodule

Answer 9

encapsulated and well circumscribed solitary nodule

Question 10

follicular carcinoma

Answer 10

• similar radiological appearance and presentation to follicular adenoma
• solitary nodule, well or poorly circumscribed
• thickly encapsulated
• capsular invasion, extra-thyroidal extension or lymph-vascular invasion
• minimally invasive = good prognosis, widely invasive = bad prognosis
• majority are non functional
• may metastasise late by haematogenous spread to bone, lungs, liver

Question 11

papillary carcinoma

Answer 11

most common in thyroid cancer
often young women
strong association with ionising radiation
often multifocal - treatment is total thyroidectomy
forms papillae, with crowded cells demonstrating nuclear grooves and clear chromatin, often psammomatous calcification and fibrosis - not encapsulated
lyphatic invasion is common
underlying RET/PTC and BRAF mutations - activate MAPK pathway
good prognosis

Question 12

prognosis papillary carcinoma

Answer 12

good in young, slightly worse in older

Question 13

how many foci in papillary carcinoma

Answer 13

ofter multifocal - treatment is total thyroidectomy

Question 14

papillary carcinoma forms

Answer 14

papillae, with crowded cells demonstrating nuclear grooves and clear chromatin - not encapsulated

Question 15

anaplastic carcinoma

Answer 15

rare
older patients
often preceded by follicular or papillary thyroid carcinoma
agressive, rapidly enlarging and infiltrative neck mass with mass effect, hoarseness
often metastatic at time of presentation
often multifocal needing thyroidectomy
lymphatic invasion is common to central neck nodes

Question 16

anaplastic carcinoma metastasis

Answer 16

lose markers of thyroid differentiation by immunochemistry - when four in other organs it is hard to identify the primary tumour

Question 17

anaplastic carcinoma appearance

Answer 17

anaplastic, pleomorphic cells, mix of large and small, multi nucleation, spindled

Question 18

medullary carcinoma

Answer 18

neuroendocrine carcinoma of the thyroid
originates from C cells (neuroendocrine cells)
solitary or multifocal, cytologically variable
express neuroendocrine markers and calcitonin by immunochemistry
behaviour variable, metastasise via lymphatics or blood vessels

Question 19

medullary carcinoma may be preceded by

Answer 19

C cell hyperplasia

Question 20

medullary carcinoma secrete

Answer 20

most secrete calcitonin and have amyloid in stroma

Question 21

genetics of medullary carcinoma

Answer 21

associated with MEN2

nearly 100% lifetime risk for those with MEN2

Question 21

genetics of medullary carcinoma

Answer 21

associated with MEN2

nearly 100% lifetime risk for those with MEN2

Question 22

medullary carcinoma metastaises via

Answer 22

lymphatics or blood vessels

Question 23

thyroid function tests

Answer 23

blood tests

• TSH, free T3/T4
• anti thyroid antibodies - if autoimmune disease suspected
• serum calcitonin

Question 24

FNA cytology for thyroid

Answer 24

for determination of benign vs malignant nodules | minimally invasive, low risk, accurate

Question 25

histopathology and immunochemistry if thyroid is resected

Answer 25

used for final diagnosis and staging of disease