Thyroid Pathology Flashcards
WHere does the thyroid come fom embryologically?
pharyngeal epithelium!
It travels down the thyroglossal duct to get into the neck
What are things that go wrong in this embryology?
you can get a lingual thyroid in the tonge
you can get thyroglossal duct cysts
malformations with thymus in the thyroid or parathyroids in the thyroid
What does the hypothalamus release to the pituitary to stimualte the thyroid
TRH
What does the pituitary use to stimualte the thyroid?
TSH
What are the two things TSH makes the thyroid do?
- makes it synthesize and release hormone
2. makes it grow
What does T4 do?
brain development
bone growth
beta-adrenergic effects
BMR increase
If T4 is high, TSH is ____
low (negative feedback)
If TSH is normal, the thyroid is ____
fine. period.
Which is a more sensitive test - TSH or T4?
TSH.
because a small change in T4 elicits a big change in TSH. if someone is becoming hyper or hypothyorid, the T4 will look like it’s still in the normal range, but TSH will go wacky right away.
If you have high T4 and low TSH, what is it?
you know it’s hyperthyroidism (high T4)
TSH SHOULD be low with high T4, so that means it’s primary hyperthyroidism.
If you have higher T4 and high TSH?
You know that the pituitary isn’t responding appropriately to the high T4, so you know it’s sdcondary hyperthyroidism (with an issue in the pituitary)
Low T4 and high TSH?
low T4 = hypothyroidism
and the TSH shoul dbe high in response, so primary hypothyroidism
Low T4 and low TSH?
the TSH should be high in response, bu it’s not = secondary hypothyroidism
If the T4 is normal, but the TSH is low?
subclinical hyperthyroidism
If the T4 is normal but TSH is high?
subclinical hypothyroidism
If the TSH is normal, but the T4 is high or low?
the test probably got messed up - reorder it
What antibody tests can you look for when evaluating the thyroid?
anti=peroxidase Ab
anti-thyroglobulin Ab
anti-TSH Ab
note - can either look in the serum or take a biopsy of the thyroid and stain for them
What is radioiodine scanning?
you use a radioactive iodine, inject it into the blood
it will go to the thyroid and then you can take an image of it - helps identify nodules that are cancerous - but doesn’t tell you for sure. so just do a biopsy
What’s the difference between a hot nodule and a cold nodule?
which is more likely cancer?
hot nodules makes hormone
cold nodule doesn’t
most cancers are cold, but not all cold nodules are cancer
What is hyperthyroidism?
a hypermetabolic state caused by increased thyroid hormone
What are some of the findings of hyperthyroidism?
jittery
weight loss, heat intolerance
rapid pulse, arrhythmias,
tremor, emotional lability, warm and moist skin, diarrhea, lid lag
What is a thyroid storm?
happens in patients who aren’t well controlled
if they get sick or stressed, the thyroid can just release all the T4 that it has - bad news - can kill the patient with heart arrhythmias
What are the thre most common causes of hyperthyroidism?
Graves disease
Multinodular goiter
Thyroid adenoma
What are the uncommon causes of hyperthyroidism?
thyroiditis drugs thyroid carcinoma pituitary adenoma struma ovarii factitious - taking hormone
WHat is hypothyroidism?
a hypometabolic state caused by decreased thyroid hormones
What are the signs and symptoms of hypothyroidism?
fatigue, weight gain, col dintolerance, slow pulse, impaired muscle contraction, delayed reflexes, lethargy, rough and dry skin, hair loss, reduced appetite, constpiation, deepend voice, “edema”,
What is myxedema?
Myxedema is NOT edema becaus eyou don’t have fluid fuilding up in the tissue
instead, the tissue is full of other substances like ground substance - they accumulate in the tissue and make them look swollen
can happen anywhere - legs, face, throat (hoarse voice)
How about a myxedema coma?
opposite of a thyroid storm
suddenly stop secreting anything - heart can stop and mental functioning drops to the point of coma
often in elderly female during cold weather, but can be anyone with hypothyroid
has NOTHING to do with the myxedema. and not everyone who gets the coma has myxedema - in fact, most don’t
myxedema is just an old term that was used for hypotyroidism.
What are potential causes of congenital hypothyroidism?
iodine deficiency
rarely genetic problems
What is the treatment for congenital hypothyroidism?
thyroid hormone replacement
but prevention is better! Fortified salt!
WHat are the two common causes of ACQUIRED hypothyroidism?
hashimoto thyroiditis
iatrogenic
What are the uncommon causes of acquired hypothyroidism?
goiter infiltrative stuff too much iodine secondary hypothyroidism tertiary hypothyroidism other thyroiditis
What is thyroiditis?
inflammation of the thyroid gland
Which gender gets thyroiditis more often?
females
What will happen with radioactive iodine uptake in thyroiditis?
decrease
What are the four types of thyroiditis?
- Hashimoto
- DeQuervain
- Silent
- Reidel
What is the most common thyroiditis?
hashimoto’s
it is SUPER common
True or false: hashimotos is very painful
false - painless
Does hashimotos lead to hypothyroidism or hyperthyroidism?
hypothyroidism
Which toy story character is Hashimoto thyroiditis?
Mrs. Potatohead
female “hash” who’s big - because they get myxedema and when you push your finger into her there won’t be an indent (non-pitting)
What anti-thyroid antibody test will usually be positive in Hashimoto thyroiditis?
anti-peroxidase antibody
but the anti-TSH can be positive too
What does Hashimoto thyroiditis look like grossly?
It’s big, firm and pale (whereas it’s usually beefy and red)
it’s pale because of all the white cells
What does Hashimoto thyroiditis look like microscopically
Tons of lymphocytes (true of all the thyroiditises)
whopping infiltrate - often makes germinal centers (can look like a lymph node)
What are the characteristic cells seen on histology in Hashimoto thyroiditis?
Hurthle cells
these are follicular cells that become reactive and respond to the infiltrate and injury by becoming big and pink with granular cytoplasm
this is totally specific for hashimotos
What do T cells do in Hashimoto thyroiditis?
they attack the thyroid cells and stimulate B cells to be unwitting accomplices (make anti-TSH receptor antibody, anti-thyroglobulin antibody, and anti-peroxidase antibody)
What is another name for Dequervain Thyroiditis?
Granulomatous thyroiditis
Is Dequervain thyroiditis painful?
yup - makes a big and sore thyroid
comes on suddenly too, so it can be quite scary
What will be in the recent medical history for DeQuervain Thyroiditis?
a recent viral URI
Does DeQuervain make hypothyroidism or hyperthyroidism?
hyperthyroidism early on
True or false: DeqUervain thyroiditis is usually self-limiting.
true
What toy story character is Dequervain thyroiditis?
Rex - he looks scary, but he’s actually harmless
What will DeQuervain thyroiditis look like microscopically?
there will be a lymphoid infiltrate
multinucleated giant cells too
Why does Dequervain make hyperthyroidism?
because it damages follicles which allows colloid to leak out
What is the foreign-body giant cell reaction to in DeQuervains?
the colloid in the extrafollicular space
When does silent thyroiditis usually present?
post-partum or during middle age
Does silent thyroiditis cause hypo or hyperthyroidism?
mild hyperthyroidism early on
What toy story character is silent thyroiditis?
Bullseye - because he doesn’t talk
also doesn’t cause any real problems
What will silent thyroiditis have on histology?
lymphoid infiltrate
other than that there are no characteristic findings. So if there is lymphoid infiltrate with no multi-nucleated giant cells and no germinal centers or hurthel cells, it’s probably silent
What is the pathogenesis of silent thyroiditis?
We don’t really know, but probably immune.
Maybe inherited? HLA? Maybe some autoantibodies?
What is the rarest thyroiditis we learned?
Reidel Thyroiditis
How will reidel thyroiditis present? Hyper or hypo?
rock-hard neck mass
hypothyroidism
tracheal compression
What is the other name for Reidel thyroiditis?
fibrosing thyroiditis
Which toy story character is Reidel thyroiditis?
woody because pathologist will call it a woody mass due to all the fibrosis
What will Reidel look like grossly?
just a really hard fir glob of scar tissue - it won’t look anything like a thyroid
What will Reidel look like microscopically
you may see a few follicles, but it’s mostly lymphocytes and then tons of fibrosis
eventually the fibrosis will just take over the whole thing
Describe the pathogenesis of Reidel THyroiditis.
we don’t really know
probably autoimmune
What is the triad of Graves Disease?
hyperthyroidism
ophthalmopathy
dermopathy
Describe the dermopathy you see in Graves.
It’s rough, scaly, thickened skin usually on the anterior lower legs
What will happen with the radioactive iodine scan in the context of Graves Disease?
diffuse increased uptake
because it’s using all the iodine to make it’s excess hormone
What will you see microscopically in Graves Disease?
it looks really busy
there are so many follicles working that they’ll sort of bulge into the colloid to make what looks like papillae
makes the colloid look scalloped
there will be so many cells that you’ll hardly be able to tell it’s thyroid
What is the most common antibody found in Grabes disease?
anti-TSH receptor antibodies
If there are antibodies against the TSH receptor, then why does Graves cause a hyperthyroidism?
because the antibodies are stimulating antibodies
Do you get the opthalmopathy with other forms of hyperthyroidism, or just Graves?
it’s specific to graves because there are TSH receptors in the tissue behind the eye for some reason
so these activating antibodies bind there and cause all sorts of problems like inflammation and deposition of things like glycosaminoglycs ans and hyaluronic acid. this is what makes the eye bulge out
note - this is the same mechanism of the pre-tibial dermopathy (the pre-tibial fibrlblasts have TSH receptors0
What are the treatments to decrease the symptoms of Graves>
What are the treatments fo decrease thyroid hormone synthesis?
Beta blockers or surgery if necessary
drugs to decreased thyroid hormone synthesis or ablation with 131-I or surgery
What is a goiter?
just a term for a big thyroid gland
In general, what are the two different causes of goiter?
- inflammatory (thyroiditis)
2. non-inflammatory (defective T4 synthesis)
Why does decreased T4 productoin cause a goiter?
because the low T4 will make the pituitary keep releasing TSH. So TSH becomes elevated and essentially tries to whip the thyroid into action, making it grow and grow and grow
so if you have no iodine, you get a goiter
At first the goiter is just a simple goiter, meaning it’s anormal shape, but big. What happens after a while though?
THe goiter will continually undergo the process of getting bigger. the follicle will try to make more hormone, so you get proliferation in some areas but no tin others so you have areas of hyperplasia and areas of involution
the follicles can rupture and the body will respond by laying down scar tissue
as this keeps happening, over time you’ll build nodules in the thyroid, which is called a multinodular goiter
When you’re at the simple goiter stage, what will you T4 levels be?
euthyroid - the thyroid is able to compensate appropriately under the rule of the pituitary TSH increase
WHen you’re at the multinodular goiter stage, what will your T4 levels be?
can be euthryoid, can be hyperfuncitoning nodules (hyperthyroid) or hypothyroid
What will goiter look like on microsocpy?
you get hyperplasia of the follicles and involution where they don’t have their usually round shape anymore
How do we typically treat a goiter?
- try levothyroxine
2. thyroidectomy
Why should you beware of giving iodine to someone with a goiter?
they have a big thyroid, right? So if you suddenly give them iodine, they can use it to make TONs of T4. That’s bad because it can kill them with heart arrhythmias
Nodules are super common. Most are _____
benign
True or false: a nodule is more likelyto be cancer if the patient is female.
false - male
True or false: a nodule is more likely to be cancer if it is solitary?
true
True or false: a nodule is more likely to be cancer if it is cold.
true
hot nodules are never cancer (but most cold nodules are not cancer either)
What medical history would make a thyroid nodule more likely to be cancer?
head or neck radiation
What do we do if we feel a nodule?
we do a thyroid fine needle aspiration with cytopathology
What are the three options for what a aspiration could show? Which ones would make you take the nodule out?
- cancer - take it out
- just follicles - take it out
- thyroiditis - treat it, leave the nodule in
Why must you take a nodule out if the biopsy shows just follicles? Arent they supposed to be there?
ther eis a cancer of the thyorid called follicular caricnoma which would only show follicular cells on biopsy
Which is by far more common for the thyroid: carcinoma or adenoma?
adenoma - like 10x more
Will most patients with a thyroid adenoma be euthyroid, hypothyroid or hyperthyroid?
most are euthyroid
some are hyperthyroid
so TSH and T4 are usually normal and most adenomas are cold
Are thyroid adenomas usually solitayr or multiple?
Do they have a capsule?
Can they invade?
usually solitary
encapsulated
no invasion
Thyroid adenomas are never malignant, but can have mutations in what family?
G-protein gain of function mutation
How can you tell the different between an adenoma and a follicular carcinoma?
adenoma wn’ tinvade the capsule
follicular carcinoma will
What are the four differnt types of thyroid cracinoma in order of incidence?
papillary - 80%
follicular - 10%
medullary 5%
anaplastic - 5%
What patient group gets papillary thyroid carcinoma?
females more than males
in their 30s-50s
Where is metastasis common for papillary thyroid carcinoma?
local lymph nodes only - visceral metastasis is super rare
What is the prognosis for papillary thyroid carinoma?
excellent
over 95% 10 year survival rate
What will papillary thyroid carcinoma look like grossly?
you cut it open and you’ll see just a bunch of cystic structures
What will a papillary thyroid carcinoma look like microscopically?
there will be chords of fibrovascular tissue which clearly appear papillary
What type of cells are classsic for papillary carcinoma?
orphan annie nuclei
the nuclei will be optically clear, which is weird and look like orphan annie eyes
What other deposit will you see microscopically in papillary carcinoma?
psammoma bodies
collections of calcium that form a concentric lamellated structure
Describe the pseudoinclusion you see in papillary carcinoma.
the cytoplasm invaginates into the nucleus so it looks like there’s a bubble inside of it
What else can you see invlving the nucleus besides pseudoinclusions in papillary carcinoma?
nuclear grooves - make the nucleus look like a coffee bean
Why can papillary carcinoma be thought of as the litle orphan annie tumor?
- affects younger women
- tends to stay around for years iwthout getting any bigger
- usually well behaved and seldom kills people
- has nuclei that resemble her eyes
- has psammoma bodies (psammos = sand, her dog’s name is sandy)
What patient group gets follicular thyroid carcinoma?
females more than males
in their 40s-50s
If metastases are present in follicular htyroid carcinoma, where do they tend to be?
lung or bone
What is the 10 year survival rate in a young patient with a small, minimally invasive tumor?
95%, so pretty good
but prognosis worsens with increasing age, tumor size and invasiveness
What will follicular thyroid carcinoma look like?
you get a lot of follicular cells trying to make follicles, but failing
oftentimes it looks exactly like normal tissue or a thyroid adenoma, so that’s why you need to look for invsion into the capsule or a blood vessel within the capsule
Medullary thyroid carcinoma is uncommon, but what is it a malignancy of?
C cells
What patient population gets medullary thyroid carcinoma?
females more than males
in their 50s-60s
True or false; most medullary thyroid carcinomas ar efamilial?
false
What is the 10 year survival for medullary carcinoma htat is confined to the thyroid? How about if mets are present?
90% if confined to the thyroid
20% if distant mets are present
What will you see microscopically in medullary thyroid carcinoma?
you’ll see a bunch of pink wtuff which is AMYLOID! Not colloid! So apple green birefringence on polarized light
also, the follicular cells will have salt and pepper appearing nuclei
Anaplastic thyroid carcinoma is super rare. What patient group gets it?
females more than males
50-60s
Describe how a anaplastic thyroid carcinoma presents?
it’s a bulky, fast-growing invasive neck mass
Why does anaplatsic thyroid carcinoma have such a bag prognosis?
it’s uusally metastatic at diagnosis
less than 10% survival rate at 5 years
What will an anaplastic thyroid carcinoma look like microscopically?
hardly anything - the cells won’t even try to form follicles
cells will just look ugly - lot of size differences
