Approach to the Thyroid Nodule

Question 1

label the basic thyroid anatomy

Answer 1

Question 2

besides a thyroid nodule, what else could the neck mass be?

Answer 2

1. congenital; thyroglossal duct cysts, branchial cleft cysts, dermoid cysts
2. inflammatory: infection, abscess, lymphadenitis
3. neoplastic: metastatic lymph nodes, salivary gland tumors, carotid body tumors

Question 3

enalrged thyroid?

Answer 3

no. branchial cleft cysts

Question 4

enlaarged thyroid?

Answer 4

no. submandicular gland tumour; pleomorphic adenoma. it’s too high and lateral.

Question 5

enlarged thyroid?

Answer 5

yes. huge goiter

Question 6

Prevalence of Thyroid Nodules

 Palpable in 5-10% of all adults

 Incidental discovery on ultrasound up to 50%!

 Autopsy ~ 50% +

 ~ 5-10% of all nodules are malignant

which gender is more predisposed to thyroid nodules? age?

Answer 6

females>males :3-4x more prevalent

• age; nodules found in >70% of people over the age of 70.
• countries/regiosn with lower iodine intake or rate of iodine supplementation of salt

Question 7

benign causes of thyroid nodules

Answer 7

• multinodular goiter
• hashimoto’s thyroiditis (causes hyerthyroid in early stages)
• cysts; collod, simple, hemorrhagic
• follocular adenomas; macro or micro follicular
• hurthle cell adenomas

Question 8

general aspects of physcial exam when looking at a neck nodules

Answer 8

1. location
2. does it move while swallowing?
3. size
4. texture
5. borders
6. tenderness
7. fixed or free?
8. pulsaltality
9. other symptoms

Question 9

malignant causes of thyroid nodules

Answer 9

1. papillary
2. follicular
3. hurthle cell
4. poorly diferentiatied
5. medullary
6. thyroid lymphoma
7. anaplastic
8. metastatic

Question 10

note different pathogenesis/causes of thyroid cancers

Question 11

clinical features HIGHLy SUSPICIOUS for malignancy

1. rapid growth, especially if on L-__
2. very __ or __ nodule
3. __ to adjacent strucures
4. new persistent __ due to vocal cord paralysis
5. regional __ in the lymph nodes
6. distant __
7. FAMILY HISOTYR of __ __ Cancer or ___ gene

Answer 11

1. rapid growth, especially if on L-THYROXINE
2. very FIRM or HARD nodule
3. FIXATION to adjacent strucures
4. new persistent HOARSENESS due to vocal cord paralysis
5. regional LYMPHADENOPATHY in the lymph nodes
6. distant METASTASES
7. FAMILY HISOTYR of MEDULLAR THYROID Cancer or MEN2

Question 12

Clinical features that increase suspicion for malignancy

1. history of head and neck __ treatment
2. large _ nodule >4cm
3. symptoms of COMPRESSION: __ or __
4. incidental discovery on a __ scan.

Answer 12

1. history of head and neck RADIATION treatment
2. large SOLIDARY nodule >4cm
3. symptoms of COMPRESSION: STRIDOR or DYSPHAGIA
4. incidental discovery on a PET scan.

Question 13

Work-up and approach to a thyroid nodule:

imaging; all palpable thyroid nodules and all nodules found incidnetally with other modalities need a dedicated thyroid __.

labs; __ ALONE is all that is required.

Answer 13

imaging; all palpable thyroid nodules and all nodules found incidnetally with other modalities need a dedicated thyroid ULTRASOUND.

labs; TSH ALONE is all that is required.

Question 14

4 key features on ultrasound of a thyroid nodule that may suggest higher cancer risk

Answer 14

1. microcalcification
2. irregular borders
3. taller than wide
4. hypoechoic.
   - a combination of these features increases cancer suspicion.
   - cannot differentiate between benign and malignant, but may help you to risk stratify nodules for risk of malignancy. You can prioritize the need for biopsy/more frequent evaluation

Question 15

evaluate

Answer 15

Spongiform nodule- almost always benign

Question 16

___ alone is the only lab value you need to start out with

Answer 16

TSH alone is all that is required.

• ONLY if your TSH is LOW will you work-up change. It raises suspicion of TOXIC or HOT nodules. Then you need a Thyroid SCAN.
• Normal or high TSH will not change your subsequent investifation plan.

Question 17

• ONLY if your TSH is ___ will you work-up change. It raises suspicion of __ or ___ nodules. Then you need a Thyroid SCAN.

Answer 17

• ONLY if your TSH is LOW will you work-up change. It raises suspicion of TOXIC or HOT nodules. Then you need a Thyroid SCAN.
• Normal or high TSH will not change your subsequent investifation plan.

HOT nodules have a LOW TSH.

Question 18

___ nodules have a LOW TSH

• ___ ___ or toxic hot thyroid follicular adenomas.
• HOT nodules almost always are ___.
• ___ in the TSH receptor alters receptor ___ to the “active” position, which causes LIGAND ___ signal transduction.

This causes constitudivve activation of __-__ RESULTING IN __ thyroid hormone production and thus a ___ TSH.

Answer 18

HOT nodules have a LOW TSH

• AUTONOMOUSLY FUNCTION or toxic hot thyroid follicular adenomas.
• HOT nodules almost always are BENIGN.
• MUTATION in the TSH receptor alters receptor CONFORMATION to the “active” position, which causes LIGAND INDEPENDENT signal transduction.

This causes constitudivve activation of GS-ALPHA RESULTING IN ELEVATED thyroid hormone production and thus a LOW TSH.

Question 19

hot or cold nodule

Answer 19

hot nodule

Question 20

hot or cold nodule

Answer 20

cold nodule.

Question 21

What is the criteria to have a fine need aspirate?

Answer 21

FNA if >1.5cm.

follow if >1.0cm

no FNA or follow up if <1.0cm

Question 22

Fine Needle Aspiration Biopsy

___ ___is preferred. Better samples; target non-palpable and the solid component of a mixed solid/cystic nodule

• Complications include BLEEDING but it is rare.
• in theory, useful results 80%.
• has reduced unnecessary surgery by 50%

Answer 22

Fine Needle Aspiration Biopsy

ULTRA SOUND GUIDANCE is preferred. Better samples; target non-palpable and the solid component of a mixed solid/cystic nodule

• Complications include BLEEDING but it is rare.
• in theory, useful results 80%.
• has reduced unnecessary surgery by 50%

Question 23

Answer 23

BENIGN epithelial cells, colloid, and occasional macrophages, typical of a “colloid nodule

Question 24

Answer 24

Follicular lesion- Indeterminate

Question 25

Answer 25

MALIGNANT Epithelial cells in a papillary formation from a papillary thyroid carcinoma. Nuclear grooves are also apparent

Question 26

Outline an integrated algorithm for work=up of a thyroid nodule-- when to do imaging, when to do labs etc.

Answer 26

1. history and TSH 2. TSH is normal or high: DO ULTRASOUND - if TSH is low, do a THYROID SCAN 3. FNA

Question 27

treatment options for BENIGN noduels

Answer 27

1. observation 2. annual nexk exam 3. repeat thyroid ultrasoun in 2 years. If nordule is unchanged, no more routine U/S needed. 4. Radioactive iodine for HOT NODULES only 5. ETHANOL or THERMAL ABLATION is uncommon unless there's cosmetic issues.

Question 28

Treatment options for INDETERMINATE NODULES (Risk 6-40%): you must explain options to the patient.

Answer 28

1. close observation. repeat thyroid ultrasound in 6 months 2. repeat DNA biopsy 3. molecular testing on FNA ample for mutations 4. surgical consult for a diagnostic lobectomy.

Question 29

treatment options for malignant or suspicious nodules

Answer 29

NEED SURGERY -Stratification for possible post-op adjuvant therapy such as radioiodine.

Question 30

 40 year old healthy female for a routine exam  You see & palpate a 2 cm right-sided neck lump:  non-tender, well-circumscribed & freely moveable  no palpable nodes or other masses  The rest of your exam is negative **- characterize this ultrasound finding. What's next to do?**

Answer 30

2 cm solid nodule - hypoechoic - irregular border - wider than tall - microcalcifications noticeable. - given that it is irregular with microcalcifications, an FNA od the node whould beone. FNA would show epithlial cells in a **papillar fomration from a pillary thyroid carcinoma. nuclear grooves are also apparent.**

Question 31

\_\_\_ THYROID CANCER is the most common. - usually diagnosis is made iwth a __ \_\_ BIOPSY. - the classic findings of papillary thyroid cancer is __ CELLS, __ \_\_ INCLUSIONS, and __ BODIES. - usually more AGGRESSIVE, tall looking cell and diffuse \_\_

Answer 31

PAPILLARY THYROID CANCER is the most common. - usually diagnosis is made iwth a FINE NEED BIOPSY. - the classic findings of papillary thyroid cancer is EPITHELIAL CELLS, INTRA NUCLEAR INCLUSIONS, and PSAMMOMA BODIES. - usually more AGGRESSIVE, tall looking cell and diffuse SCLEROSING

Question 32

which gender is more likely to be affected by thyroid cancer?

Answer 32

WOMEN are three times more common than men. it is the fastest rising incidence of all cancers in the past decade

Question 33

T/F we should start screening for thyroid cancer

Answer 33

false. screening that results in the identification of indolent thyroid cancers and treatment of these overdiagnosed cancers may increase the risk of patient harms.

Question 34

5 classifications of thyroid cancer, what is the most common?

Answer 34

1. differentiated thyroid cancer (most common)- papillar, folluclar, hurthle cell 2. poorly differentiated 3. medullary 4. anaplastic 5. thyroid lymphoma

Question 35

pathogenesis of thyroid cancers SPONTANEOUS or \_\_-induced chromosomal gene \_\_: usually from chimeric genes like RET/PTC. BRAF V600E. - Unregulated __ KINASE activity which increases tumor development and growth - activatingmutations in __ genes like RAS which can cause \_\_- __ Dysregulation - Silencing of tumor ___ genes like DNA HYPERMETHYLATION. - only 5% of all papillary cancers are familial

Answer 35

SPONTANEOUS or RADIATION-induced chromosomal gene REARRANGEMENT: usually from chimeric genes like RET/PTC. BRAF V600E. - Unregulated TYROSINE KINASE activity which increases tumor development and growth - activatingmutations in REGULATOR genes like RAS which can cause CELL- CYCLE Dysregulation - Silencing of tumor SUPPRESSOR genes like DNA HYPERMETHYLATION. - only 5% of all papillary cancers are familial

Question 36

outline the different types of cancers that are more and more de-differentiated

Answer 36

Question 37

SURGERY - should be done with __ TO __ MONTHS of diagnosis - near-total ___ usually recommended for leasions \>\_\_CM. - if under 1 cm, it's called a __ and not treated aggressively. We should actively surveille. - recent ATA guidelines suggest the option for a __ for **_low risk patients._**

Answer 37

- should be done with 6 TO 12 MONTHS of diagnosis - near-total THYROIDECTOMY usually recommended for leasions \>1CM. - if under 1 cm, it's called a MICROCARINOMA and not treated aggressively. We should actively surveille. - recent ATA guidelines suggest the option for a lobectomy for low risk patients.

Question 38

5 steps to the post-operative plan

Answer 38

after surgery: 1. evaluate final pathology 2. staging to help predict mortality and recurrence 3. thyroid hormone replacement and intensity 4. discuss possible need for radioactive iodine 5. outline follow up plan

Question 39

most staging systems are designed to predict the risk of moratlity. what are the two staging systems