Thyroid Cancer

Question 1

what is the most common thyroid cancer and who does it usually occur in?

Answer 1

papillary thyroid carcinoma

usually in young females

Question 2

prognosis of papillary cancer?

Answer 2

very good

Question 3

what is a medullary thyroid carcinoma and what disease is it a feature of?

Answer 3

cancer of parafolicular (C) cell which secrete calcitonin

feature of MEN2

Question 4

how is papillary/follicular thyroid carcinoma managed?

Answer 4

total thyroidectomy or lobectomy
followed by radioiodine (I-131) to kill any residual cells
annual check up which tests thyroglobulin levels to detect any recurrence

Question 5

describe papillary thyroid carcinoma

Answer 5

mixture of papillary and colloidal filled follicles
papillary projections (fingers) and pale empty nuclei on histology
usually not encapsulated
invades nearby lymph nodes

Question 6

how do papillary thyroid carcinomas spread?

Answer 6

lymphatically

Question 7

describe follicular carcinoma

Answer 7

may be encapsulated
often a single lesion
grows and breaks through the fibrous capsule and invades nearby blood vessels

Question 8

how does follicular carcinoma spread?

Answer 8

haematogenously

Question 9

describe medullary carcinoma

Answer 9

tumour of C cells (derived from neural crest, not thyroid tissue)
usually in upper 1/3rd of thyroid as concentration of C cells is higher here
raised serum calcitonin levels
both lymphatic and haematogenous spread
usually a single lesion in one lobe

Question 10

what is the most severe thyroid cancer and who does it usually occur in?

Answer 10

anaplastic carcinoma

usually in older females

Question 11

what does calcitonin do?

Answer 11

lowers circulating calcium by inhibiting osteoclasts

reduces renal tubule reabsorption of calcium

Question 12

papillary and follicular carcinomas are both part of what group of thyroid cancer?

Answer 12

differentiated

- cells look and act normally?

Question 13

what is the development of papillary carcinoma associated with?

Answer 13

RET and BRAF mutations

exposure to radiation

Question 14

2nd most common thyroid cancer?

Answer 14

follicular

Question 15

what is the development of follicular carcinoma associated with?

Answer 15

cultures with low dietary iodine
activation of RAS oncogene
deactivation of PTEN tumour suppressor

Question 16

what are hurthle cells and when are they typically seen?

Answer 16

follicular cells in the thyroid adapt to stress (e.g inflammation) by turning into hurthle cells by increasing production of mitochondria (causes granular appearance and cells stain pink)
seen in hurthle cell carcinoma variant of follicular carcinoma) and hashimotos thyroiditis (due to inflammation)

Question 17

what causes medullary thyroid carcinoma?

Answer 17

20% due to MEN2
can be familial
RET mutation

Question 18

medullary carcinoma histology?

Answer 18

spindle shaped cells

deposits of calcitonin(which turn into amyloids) around cells

Question 19

anaplastic carcinoma histology?

Answer 19

spindle cells

pleomorphic giant cells

Question 20

first signs of thyroid cancer?

Answer 20

solitary, hard, immovable, painless nodule in the neck
hoarseness (if invading larynx)
trouble swallowing (if invading oesophagus)

Question 21

how do thyroid cancers affect thyroid function?

Answer 21

usually normal thyroid function

most thyroid cancers are non-functional

Question 22

how might a medullary thyroid carcinoma present specifically?

Answer 22

tumour releases vasoactive intestinal peptide - diarrhoea

tumour releases serotonin = flushed skin

Question 23

how is thyroid cancer diagnosed?

Answer 23

US
calcitonin levels (medullary)
radioiodine scan (thyroid cancer cells don't uptake iodine as they don't make thyroid hormone)
FNA = definitive