Endo

Question 1

Adrenal anatomy

Answer 1

The adrenal glands are paired retroperitoneal glands that sit on each kidney.
The right gland is triangular in shape, and the left gland tends to be more crescent shaped. If
the kidney is congenitally absent the glands will be more flat, straight, discoid, or “pancake ”
in appearance. Each gland gets arterial blood from three arteries (superior from the inferior
phrenic, middle from the aorta, and inferior from the renal artery). The venous drainage is via
just one main vein (on the right into the IVC, on the left into the left renal vein).

Question 2

adrenal cortex layers

Answer 2

Zona glomerulosa
zona fasciculata
zona reticularis

Question 3

Adrenal 4 zones

Answer 3

Zona Glomerulosa: Makes Aldosterone
- prolonged stimulation here leads to hypertrophy.
Zona Fasciculata: Makes Cortisol
Zona Reticularis — Makes Androgens
Medulla - Makes Catecholamines

Question 4

Adrenal Ultrasound Cases - Gamesmanship

overview

Answer 4

If you get shown an adrenal case on ultrasound, then you are almost certainly dealing with a
peds case. What that means is that your choices are narrowed down to: (a) normal,
(b) neuroblastoma, (c) hemorrhage, and (d) hyperplasia.

Question 5

Adrenal Ultrasound Cases - Gamesmanship

normal

Answer 5

In babies, the cortex is hypoechoic, and the medulla is hyperechoic. This gives
the adrenal a triple stripe appearance (dark cortex, bright medulla, dark cortex).

Question 6

normal adrenal us quick

Answer 6

Hypoechoic Cortex, Hyperechoic Medulla, Hypoechoic Cortex

- like an Oreo, with a cream filling.

Question 7

Neuroblastoma (adrenal)

Answer 7

I talk about this a ton in the peds chapter. To rehash the
important parts, they form in the adrenal medulla
(usually), and typically look like an enlarged gland with
a hyperechoic component. Having said that they can
have cystic components and look like hemorrhage. For
the purpose o f multiple choice I ’d go with hyperechoic.

Question 8

Adrenal hemorrhage

overview

Answer 8

This occurs most commonly in the setting of
trauma or stress (neonates). What this typically
looks like on ultrasound is an enlarged gland with
an anechoic component. With time, the clot
changes and it can be more and more echogenic.
So basically, it can look like anything but for the
purpose o f multiple choice I’d go with anechoic.

Question 9

Adrenal hemorrhage

stress

Answer 9

It’s classically seen after a breech birth, but can also be seen with fetal
distress, and congenital syphilis. Imaging features change based on the timing of
hemorrhage. Calcification is often the end result (that could be shown on CT or
MR). It should be avascular. This can occur bilaterally, but favors the right side
(75%).
o Classic Next Step: Serial ultrasounds (or MRI) can differentiate it from a
cystic neuroblastoma. The hemorrhage will get smaller (cancer will not).
o So which is it? Serial ultrasound or MRI? - If forced to pick you want serial
ultrasounds. It’s cheaper and doesn’t require sedation.

Question 10

Adrenal hemorrhage

trauma

Answer 10

This is going to be an adult (in the setting o f trauma). Most likely it will be shown on CT. It’s more common on the right.

Question 11

Waterhouse-Friderichsen Syndrome

Answer 11

Hemorrhage o f the adrenal in the

setting of fulminant meningitis (from Neisseria Meningitidis).

Question 12

Adrenal hyperplasia

overview

Answer 12

What this typically looks like on ultrasound is a “big
adrenal” that “looks like a brain.” So what does “b ig ”
mean ? Most sources will say longer than 20mm, and a
limb that is thicker than 4 mm (although this is debated -
and will likely not be asked). For the purpose o f multiple
choice I would say that if they stick calibers on it. then it is
too big. So what does “looks like a brain ” mean ? That
means the surface is wrinkled, like it has gyri and sulci.

Question 13

Adrenal hyperplasia

21-Hydroxylase Deficiency:

Answer 13

Congenital adrenal hypertrophy is caused by 21-
hydroxylase deficiency in > 90% o f cases. It will manifest clinically as either genital
ambiguity (girls) or some salt losing pathology (boys). The salt losing can actually be
life threatening. The look on imaging is adrenal limb width greater than 4mm. In some
cases you lose the central hyperechoic stripe (the whole thing looks like cortex).

Question 14

Adrenal hyperplasia

Too much cortisol

Answer 14

from overproduction o f ACTH - which results in bilateral
adrenal gland hyperplasia. If someone wanted to be a real asshole they could get into the
weeds with vocabulary. For example, the “Disease” vs “Syndrome” THIS vs THAT:

Question 15

I say “Genital ambiguity”, you say

Answer 15

21-Hydroxylase Deficiency

Question 16

Cushing Disease:

Answer 16

This is an overproduction o f ACTH by a pituitary adenoma,

resulting in too much cortisol. This is actually the most common cause o f excess cortisol (75%).

Question 17

Cushing Syndrome

Answer 17

The “syndrome” is basically a variety o f causes resulting
in common symptoms. So you can have overproduction o f ACTH by an ACTH
secreting tumor (classic step 1 example is the small cell lung tumor), or
overproduction o f ACTH via an adrenal adenoma (these cases will not have
hyperplasia), or you can have straight up primary adrenal hyperplasia. You could even
get the “syndrome” by taking chronic high dose steroids. Any way you end up with a
fat moon face and big gross lines all over you belly counts as “syndrome.”

Question 18

Adrenal rapid review

normal

Answer 18

" Triple Stripe
■ Hypoechoic Cortex,
“ Hyperechoic Medulla,
' Hypoechoic Cortex
■ Smooth Surface

Question 19

Adrenal rapid review

hyperplasia

Answer 19

’ Big (longer than 20mm)
■ Looks like a brain (wrinkled surface)
‘ Can sometimes lose the central bright layer
- “Genital ambiguity”, = 21-OH Deficiency

Question 20

Adrenal rapid review

hemorrhage

Answer 20

■ Big with an anechoic (or echogenic) component
■ Gets smaller over time
- Seen with “stress” or trauma

Question 21

Adrenal rapid review

neuroblastoma

Answer 21

” Big with an echogenic (or anechoic) component

- Does NOT gets smaller over time

Question 22

Adrenal Adenoma

overview

Answer 22

These things are easily the most common tumor in the adrenal gland. Up to 8% o f people
have them. Proving it is an adenoma is an annoying (testable) problem.

Question 23

Adrenal Adenoma

non con

Answer 23

less than 10 HU

Question 24

Adrenal Adenoma

absolute washout

Answer 24

Enhanced CT - Delayed CT/
Enhanced CT - Unenhanced CT
x 100

Greater than 60% = Adenoma

Question 25

Adrenal Adenoma relative washout

Answer 25

Enhanced CT - Delayed CT / Enhanced CT x 100 Greater than 40% = Adenoma

Question 26

Adrenal ademo hypervascular mets

Answer 26

``` Hypervascular mets (usually renal, less likely HCC) can mimic adenoma washout. Portal venous HU values > 120 should make you think about a met. ```

Question 27

adrenal pheo

Answer 27

Along those lines Pheochromocytomas can also exhibit washout. The trick is the same, if you are getting HU measurements > 120 on arterial or portal venous phase you can NOT call the thing an adenoma.

Question 28

adreanl adenoma mri

Answer 28

Look for drop out on in and out o f phase T l.

Question 29

Real Life = Mass in Adrenal =

Answer 29

adenoma

Question 30

Multiple Choice = Mass in the Adrenal =

Answer 30

possible stuffery

Question 31

Although most adenomas are not functional,

Answer 31

Cushings (too much cortisol) and Conn’s (too | much aldosterone) can present as functional adenoma.

Question 32

adrenal adenoma tips

Answer 32

• Adenoma are usually homogeneous. If they are showing you hemorrhage (in the absence of trauma), calcifications, or necrosis you should start thinking about other things. • Adenomas are usually small (less than 3 cm). The bigger the mass, the more likely it is to be a cancer. Hom> b ig ? Most people will say more than 4 cm = 70% chance cancer, and more than 6 cm = 85% chance cancer. The exceptions are bulk fat (myelolipomas) or biochemical catecholamines in the question stem (pheo) - those can be big. • Bilateral Small = Probably adenoma • Bilateral Large = Pheo or Met (Lung cancer) • Portal Venous Phase HU > 120 — Probably a met (RCC, HCC) or pheo.

Question 33

“Collision Tumors”

Answer 33

Two different tumors that smash together to look like one mass. Usually one o f them is an adenoma. Remember adenoma should be homogenous and small. If you see heterogenous morphology consider that you could have two tumors. FDG PET and MRI can both usually tell if the tumor is actually a collision of two different tumors - those would be the appropriate next steps.

Question 34

Conn’s Syndrome

Answer 34

Syndrome o f excessive aldosterone production. This is most commonly caused by a benign adenoma (70%). Cortical-carcinoma can also do it, but that is much more rare and usually accompanied by hypercortisolism.

Question 35

Pheochromocyioma overview

Answer 35

Uncommon in real life (common on multiple choice tests). They are usually large at presentation (larger than 3 cm). The look is variable (heterogenous, homogenous, cystic areas, calcifications, sometimes even fat). Having said that, the most classic look is a heterogeneous mass with AVID ENHANCEMENT. On MRI they are T2 bright. Both MIBG and Octreotide could be used (but MIBG is better since Octreotide also uptakes in the kidney).

Question 36

Pheochromocyioma gamesmanship 1

Answer 36

``` The hyper enhancement washout trick. They could show you what looks like an adenoma study (multiple phases to calculate washout) - but with mega enhancement (HU > 120). Remember, I don't care what the fuck washout out numbers you get - if they show you HU measurements > 120 on arterial or portal venous phase you can NOT call the thing an adenoma. ```

Question 37

Pheochromocyioma gamesmanship 2

Answer 37

This thing isn’t always in the adrenals. They can be extra adrenal (organ of Zuckerkandl - usually at the IMA).

Question 38

Pheochromocyioma rule of 10s

Answer 38

10% are extra adrenal (organ o f Zuckerkandl - usually at the IMA), 10% are bilateral, 10% are in children, 10% are hereditary, 10% are NOT active (no HTN).

Question 39

Pheochromocyioma syndromes

Answer 39

Associated syndromes: First think Von Hippel Lindau, then think MEN Ha and lib. Other things less likely to be tested include NF-1, Sturge Weber, and TS.

Question 40

Pheochromocyioma carney triad

Answer 40

* Extra-Adrenal Pheo, GIST, and Pulmonary Chondroma (hamartoma). * Don ’/ confuse this with the Carney Complex (Cardiac Myxoma, and Skin Pigmentation).

Question 41

Pheochromocyioma Men 2

Answer 41

Both subtypes o f MEN 2 are associated with Pheochromocytomas (50% o f patients). In the case o f MEN 2 they usually occur multiple and bilateral. MEN 2 + Adrenal Mass = Pheo

Question 42

Adrenal myelolipoma

Answer 42

Benign tumor that contains bulk fat. About 1/4 have calcifications. If they are big (> 4 cm) they can bleed, and present with a retroperitoneal hemorrhage. Another piece of trivia is the association with endocrine disorders (Cushings, Congenital Adrenal Hyperplasia, Conns). Don’t get it twisted, these tumors arc NOT functional, they just happen to have associated disorders about 5-10% of the time.

Question 43

adrenal cyst

Answer 43

You can get cysts in your adrenal. They are often unilateral, and can be any size. The really big ones can bleed They have a thin wall, and do NOT enhance.

Question 44

adrenal mets

Answer 44

Think breast, lung, and melanoma. They have no specific imaging findings and look like lipid poor adenomas. If the dude has a known primary (especially lung, breast, or melanoma), and it’s not an adenoma then it’s probably a met.

Question 45

adreanl cortical carcinoma

Answer 45

These are large (4 cm -10 cm), may be functional (Cushings), and calcify in about 20% of cases. They are bad news and often met everywhere (direct invasion often first). As a pearl, an adrenal carcinoma is not likely to be less than 5 cm and often has central necrosis.

Question 46

Myelolipoma quick

Answer 46

bulk fat | hyperechoic on us

Question 47

adrenal calcifications

Answer 47

This is often the result o f prior trauma or infection (TB). Certain tumors (cortical carcinoma, neuroblastoma) can have calcifications. Melanoma mets are known to calcify.

Question 48

wolman disease

Answer 48

This is a total Aunt Minnie (and massive zebra / unicorn). Bilateral enlarged calcified adrenals. It’s a fat metabolism error thing that kills (“booka” - Ali G) before the first year of life.

Question 49

MEN 1

Answer 49

``` Parathyroid Hyperplasia (90%), Pituitary Adenoma, Pancreatic Tumor (Gastrinoma most commonly) ```

Question 50

MEN 2

Answer 50

Medullary Thyroid Cancer (100%), Parathyroid hyperplasia, | Pheochromocytoma (33%)

Question 51

MEN 2b

Answer 51

Medullary Thyroid Cancer (80%), Pheochromocytoma (50%), Mucosal Neuroma, Marfanoid Body Habitus

Question 52

MEN I (3 Ps)

Answer 52

- Pituitary, Parathyroid, Pancreas

Question 53

MEN lla (1M,2 Ps)

Answer 53

Medullary Th yro id Ca, | Phe ochrom ocytoma , Parathyroid

Question 54

MEN lib (2Ms, 1P)

Answer 54

- Medullary Thyroid Ca, Marfanoid Habitus /mucosa l neuroma, | Phe o chrom oc y tom a

Question 55

Carcinoid Syndrome

Answer 55

Flushing, diarrhea, pain, right heart failure from serotonin manufactured by the carcinoid tumor. The syndrome does not occur until the lesion mets to the liver (normally the liver metabolizes the serotonin). The typical primary location for the carcinoid tumor is the GI tract (70%). The most common primary location is the distal ileum (older literature says appendix). The actual syndrome only occurs in 10% o f cases - and is actually very rare (in real life - not on tests).

Question 56

GI carcinoids are associated with

Answer 56

oterh GI tumors (GI adenocarcinoma)

Question 57

urine test for carcinoid

Answer 57

5-HIAA (5-hydroxyindoleacetic acid)

Question 58

Carcinod nukes test of choid

Answer 58

11'In-Octreotide (Octreoscan)

Question 59

systemic serotonin

Answer 59

degrades the heart valves (right sided), and classically causes tricuspid regurgitation

Question 60

VHL

Answer 60

Hemangioblastoma is the most common tumor (seen in the retina, cerebellum, spinal cord) Endolymph Sac Tumor is common (10%) Bilateral clear cell RCC (-risk -70%) Papillary Cystadeoma of the epididymis (-55%) Pheochromocytoma (risk -10%). Less likely to be associated with catecholamine production. Pancreatic Cysts (-75%) and serous cystadeomas

Question 61

PGL Syndrome (Paraganglioma & Pheochromocytoma)

Answer 61

Multiple head and neck paragangliomas (risk - 70%) Pheochromocytoma risk is variable depending on the subtype

Question 62

Tuberous Sclerosis (Bourneville Disease)

Answer 62

Clinical Triad (Facial Angiofibroma, Seizures, Retard Brain) Cortical Tubers, Subependymal Nodules, Subependymal Giant Cell Astrocytoma (SEGA) - found at the caudothalamic groove adjacent to the foramen of monro cardiac rhabdomyoma pulmonary cysts (LAM)

Question 63

MEN 1 overview

Answer 63

Parathyroid Pituitary Pancreas Less commonly carcinoids of the bronchus, and bowel Primary Hyperparathyroidism is the most common (risk - 100%), related to adenomas Prolactinoma is the most common pituitary tumor Gastrinoma is the most common pancreas / duodenal tumor — jejunal ulcers and gastric fold thickening (Zollinger Ellison)

Question 64

MEN 2 A overview

Answer 64

Medullary Thyroid Cancer Pheochromocytoma (-50%) and often bilateral Primary Hyperparathyroidism Thyroid cancers occur at younger ages and are multicentric Elevated levels of calcitonin cause flushing and diarrhea similar to carcinoid syndrome

Question 65

MEN 2 B overview

Answer 65

Medullary Thyroid Cancer Pheochromocytoma ``` Marfanoid Appearance Mucosal Neuromas Intestinal Ganglioneuromas These patients fart alot (seriously) ``` Thyroid cancers occur at younger ages and are multicentric Elevated levels of calcitonin cause flushing and diarrhea similar to carcinoid syndrome

Question 66

Familial Medullary | Thyroid (FMTC)

Answer 66

Can be considered a subtype of MEN 2

Question 67

Thyroid anatomy

Answer 67

The thyroid gland is a butterfly shaped gland, with two lobes connected by an isthmus. The thyroid descends from the foramen cecum at the anterior midline base of the tongue along the thyroglossal duct. The posterior nodular extension of the thyroid (Zuckerkandl tubercle) helps give a location of the recurrent laryngeal nerve (which is medial to it).

Question 68

Thyroid nodules

Answer 68

Usually evaluated with ultrasound. Nodules are super super common and almost never cancer. This doesn’t stop Radiologists from imaging them, and sticking needles into them. Ultrasound guided FNA of colloid nodules is a major cash cow for many body divisions, that on very rare occasions will actually find a cancer. Qualities that make them more suspicious include: more solid (cystic more benign), calcifications (especially microcaicifications). Microcalcifications are supposed to be the buzzword for papillary thyroid cancer. “Comet Tail” artifact is seen in Colloid Nodules. “Cold Nodules” on 1-123 scans are still usually benign but have cancer about 15% of the time, so they actually deserve workup.

Question 69

Thyroid colloid nodules

Answer 69

These are super super common. Suspicious features include microcaicifications, increased vascularity, solid size (larger than 1.5 cm), and being cold on a nuclear uptake exam. As above, Comet tail artifact is the buzzword.

Question 70

Ultrasound Characteristics of Thyroid Nodules calcification

Answer 70

Increased Risk • Micro x3 • Macro x2 Microcaicifications have the highest accuracy, specificity, and positive predictive value for detecting malignancy Microcaicifications = the “hallmark” o f papillary CA Macrocalcification = most common calcification in medullary CA Macrocalcifications in a single nodule = higher risk Macrocalcifications in a multi-nodule goiter = lower risk

Question 71

Ultrasound Characteristics of Thyroid Nodules margins and shape

Answer 71

Complete hypoechoic halo is highly suggestive o f benign disease irregular, spiculated, & microlobulated margins suggest malignancy

Question 72

Ultrasound Characteristics of Thyroid Nodules vascularity

Answer 72

Peripheral pattern o f flow is suggestive o f benign disease Central pattern o f flow is suggestive o f malignancy Solid hypervascular nodules are more likely to be malignant

Question 73

Ultrasound Characteristics of Thyroid Nodules echotexture

Answer 73

Solid composition has the highest sensitivity for malignancy (although not specific - many benign nodules are also solid.) Pure cystic, or spongiform with more than 50% specific are likely benign. Change over time from solid to cystic suggests benign disease Most hyperechoic or isoechoic nodules are benign. Solid Hypoechoic = feature of malignancy

Question 74

Ultrasound Characteristics of Thyroid Nodules size and multiplicity

Answer 74

Nodule size is NOT predictive o f malignancy. Suspicious features should be the primary consideration when targeting for biopsy (not size) Multiple nodules = decreased cancer rate per nodule — but the overall rate o f having cancer in one nodule is fairly constant.

Question 75

Thyroid Adenoma

Answer 75

These look just like solid colloid nodules on ultrasound. They can be hyper functioning (hot on uptake scan). Usually if you have a hyper-functioning nodule (toxic adenoma), your background thyroid will be colder than normal (which makes sense).

Question 76

Goiter

Answer 76

Thyroid that is too big. In North America it’s gonna be a multi-nodular goiter or Graves. In Africa it’s low iodine. You can get compressive symptoms if it mashes the esophagus or trachea. These are often asymmetric - with one lobe bigger than the other.

Question 77

Subacute Thyroiditis I De Quervains Thyroiditis

Answer 77

The classic clinical scenario is a female with a painful gland after an upper respiratory infection. There is a similar subtype that happens in pregnant women, although this is typically painless. You get hyperthyroidism (from spilling the hormone) and then later hypothyroidism. As you get over your cold, the gland recovers to normal function. Radiotracer uptake will be decreased during the acute phase.

Question 78

Acute Suppurative Thyroiditis

Answer 78

This is an actual bacterial infection of the thyroid. It is possible to develop a thyroid abscess in this situation. A unique scenario (highly testable) is that in kids this infection may start in a 4th branchial cleft anomaly (usually on the left), travel via a pyriform fistula and then infect the thyroid. Honestly, that is probably too much for the exam - but could show up on a certification exam under neuro.

Question 79

Reidels Thyroiditis

Answer 79

This is one of those IgG4 associated diseases (others include orbital pseudotumor, retroperitoneal fibrosis, sclerosing cholangitis). You see it in women in their 40s-70s. The thyroid is replaced by fibrous tissue and diffusely enlarges causing compression o f adjacent structures (dysphagia, stridor, vocal cord palsy). On US there will be decreased vascularity. On an uptake scan you are going to have decreased values. A sneak trick would be to show you a MR (it’s gonna be dark on all sequences - like a fibroma).

Question 80

Thyroglossal Duct Cyst (TGDC overview

Answer 80

The most common congenital neck cyst in Pediatrics. This can occur anywhere between the foramen cecum (the base o f the tongue) and the thyroid gland (or below). It looks like a thin walled cyst.

Question 81

Thyroglossal Duct Cyst (TGDC why care

Answer 81

* They can get infected * They can have ectopic thyroid tissue * Rarely, that ectopic tissue can get papillary thyroid cancer (if you see an enhancing nodule)

Question 82

Thyroglossal Duct Cyst (TGDC location

Answer 82

These are the general numbers to think about: Suprahyoid = 25% At the Hyoid = 30% Infrahyoid = 45% So, where is the most common location? Well, it depends on how they ask. If all things are equal the answer is Infrahyoid (which seems counterintuitive based on the embryology but is non the less true). BUT - if “at or above the hyoid” is a choice - then that is actually the right answer (25+30 > 45). As always, read every choice carefully.

Question 83

Ectopic and Lingual Thyroid

Answer 83

Similar to a thyroglossal duct cyst, this can be found anywhere from the base of the tongue through the central neck. The most common location (90%) is the tongue base (“Lingual Thyroid”). It will look hyperdense because o f its iodine content (just like a normally located thyroid gland). If you find this, make sure you check for a normal thyroid (sometimes this is the only thyroid the dude has). As a point of trivia, the rate o f malignant transformation is rare (3%).

Question 84

Graves

Answer 84

Autoimmune disease that causes hyperthyroidism (most common cause). It’s primarily from an antibody directed at the TSH receptor. The actual TSH level will be low. The gland will be enlarged and “inferno hot” on Doppler.

Question 85

graves orbitopahty

Answer 85

Spares the tendon insertions, doesn’t hurt (unlike pseudotumor). Also has increased intra-orbital fat.

Question 86

graves nuclear medicine

Answer 86

Increased uptake o f 1-123 %RAIU usually 50-80%. Visualization of pyramidal lobe is accentuated.

Question 87

Hashimotos overview

Answer 87

The most common cause of goitrous hypothyroidism (in the US). It is an autoimmune disease that causes hyper then hypo thyroidism (as the gland bums out later). It’s usually hypo - when it’s seen. It has an increased risk of primary thyroid lymphoma.

Question 88

Hashimotos step one triia

Answer 88

associated with autoantibodies to thyroid peroxidase (TPO) and antithyroglobulin.

Question 89

Hashimotos on ultrasound

Answer 89

(a) Heterogeneous “giraffe skin” appearance, (b) White Knights - uniform hyperechoic nodules - which are actually regenerative nodules.

Question 90

Level 6 Nodes - “Delphian Nodes”

Answer 90

• These are the nodes around the thyroid in the front of the neck. - You can commonly see them enlarged with Hashimotos. ■ However, for the purpose of multiple choice tests, a sick looking level 6 node - or “Delphian Node” is a laryngeal cancer met.

Question 91

Papillary thyroid cancer

Answer 91

The Most Common Subtype. “Papillary is Popular ” Microcalcifications is the buzzword and key finding (seen in the cancer and nodes). Mets via the lymphatics. Has an overall excellent prognosis, and responds well to 1-131.

Question 92

follicular thyroid cancer

Answer 92

The second most common subtype. Mets hematogenously to bones, lung, liver, etc.. Survival is still ok, (less good than papillary). Does respond to 1-131.

Question 93

medullary thyroid cancer

Answer 93

Uncommon Association with MEN II syndrome. Calcitonin production is a buzzword. Tendency towards local invasion, lymph nodes, and hematogenous spread. Does NOT respond to 1-131.

Question 94

anaplastic thyroid cancer

Answer 94

Uncommon Seen in Elderly. Seen in people who have had radiation treatment. Rapid growth, with primary lymphatic spread. Does NOT respond to 1-131.

Question 95

hurthle cell (varian of follicular)

Answer 95

Uncommon Seen more in Elderly. Does not take up 1-131 as well as normal follicular. FDG-PET is the way to go for surveillance.

Question 96

Thyroid mets

Answer 96

The buzzword is going to be microcalcifications in a node (with papillary). The nodes are typically hyperechoic compared to regular nodes, hyperenhancing on CT, and T1 bright on MR. Remember that thyroid cancer is hypervascular, and it can bleed like stink when it mets to the brain. If there are mets to the lungs, the classic pattern is “miliary.” The additional pearl with regard to lung mets is that they can be occult on cross sectional imaging, and only seen on whole body scintigraphy. For the purpose of multiple choice tests pulmonary fibrosis is a risk o f treating with 1-131 i f you have diffuse lung mets.

Question 97

parathyroid anatomy

Answer 97

There are normally 4 parathyroid glands located posterior to the thyroid. The step 1 trivia is that the superior 2 are from the 4th branchial pouch, and the inferior 2 are from the 3rd branchial pouch. The inferior two are more likely to be in an ectopic location.

Question 98

Parathyroid Adenoma

Answer 98

This is by far the most common cause of hyperparathyroidism (90%). On ultrasound these things look like hypoechoic beans posterior to the thyroid. A 4D-CT can be used to demonstrate early wash-in and delayed wash-out. Nuclear medicine can use two techniques (1) the single-tracer, dual-phase Sestamibi, or (2) the dual tracer Sestamibi +1-123 (or Pertechnetate). These are discussed in detail in the nukes section.

Question 99

Parathyroid Adenoma quick imaging

Answer 99

4D CT shows early enhancement, and delayed washout

Question 100

Parathyroid Carcinoma

Answer 100

This is pretty uncommon, and only makes up about 1% of the causes o f hyperparathyroidism. It looks exactly like an adenoma on imaging. The only way you can tell on imaging is if they show you cervical adenopathy or invasion o f adjacent structures.

Question 101

High Yield Parathyroid Trivia

Answer 101

Q: What are the causes o f hyperparathyroidism? A: Hyperfunctioning Adenoma (85-90%), Multi-Gland Hyperplasia (8 -10%), Cancer (1 -3%). Q: What factors does sestamibi parathyroid imaging depend on ? A: Mitochondrial density and blood flow