Neoplasm of the Thyroid Gland

Question 1

How does thyroid NEOPLASIA classically present?

Answer 1

• distinct, SOLITARY nodule.

Question 2

Are thyroid nodules more likely to be malignant or benign?

Answer 2

• BENIGN

Question 3

What study can you do if you think a pt has a thyroid neoplasia?

Answer 3

• radioactive iodine uptake study
• will see INCREASED uptake in Graves or nodular goiter.
• will see DECREASED uptake in adenoma and carcinoma (warrants FNA biopsy).

Question 4

*** If you have DECREASED radioactive iodine uptake, what type of biopsy should you do?

Answer 4

• FINE NEEDLE ASPIRATION (FNA) biopsy.

Question 5

What is a Follicular adenoma?

Answer 5

• BENIGN proliferation of follicles surrounded by a FIBROUS CAPSULE.
• usually nonfunctional; rarely may secrete thyroid hormone.
• HURTHLE cell subtype= eosinophilic cytoplasm.

Question 6

** What is a Papillary carcinoma?

Answer 6

• MOST COMMON type of thyroid carcinoma.
• forms papillary fingerlike projections.
• ORPHAN ANNIE NUCLEI= white clearing in center of nuclei.
• NUCLEAR GROOVES.
• PSAMMOMA BODY= layering of calcium.
• exposure to IONIZING RADIATION in childhood is a major risk factor.

Question 7

Where does Papillary carcinoma often spread?

Answer 7

• to cervical nodes, but has EXCELLENT prognosis :)

Question 8

** What is a Follicular carcinoma?

Answer 8

• MALIGNANT proliferation of FOLLICLES.
• surrounded by a FIBROUS CAPSULE with INVASION through the capsule.
• PI-3K/AKT, RAS, PTEN, PAX8, or PPARG mutations

Question 9

Can fine needle biopsy distinguish between follicular adenoma and follicular carcinoma?

Answer 9

• NO, bc you need to examine the capsule.

Question 10

How does Follicular carcinoma metastasize?

Answer 10

• HEMATOGENOUSLY

* odd bc normally carcinoma spreads via lymphatics.

Question 11

What is Medullary carcinoma?

Answer 11

• MALIGNANT proliferation of parafollicular C-cells (sit adjacent to follicles).
• high levels of CALCITONIN produced by tumor and may lead to HYPOcalcemia.
• calcitonin often deposits within tumor as AMYLOID; aka localized amyloidosis.

Question 12

** What are some familial cases of Medullary carcinoma of the thyroid?

Answer 12

• due to Multiple Endocrine Neoplasia (MEN2A) and (2B).
• associated with mutations in RET ONCOGENE.
• detection of RET mutation warrants prophylactic thyroidectomy.

Question 13

What 3 neoplasias are associated with MEN2A?

Answer 13

1. medullary carcinoma of THYROID
2. PHEOCHROMOCYTOMA (adrenals)
3. PARATHYROID adenoma

Question 14

What 3 neoplasias are associated with MEN2B

Answer 14

1. medullary carcinoma of THYROID
2. PHEOCHROMOCYTOMA (adrenals)
3. GANGLIONEUROMAS (particularly of oral mucosa).

Question 15

*** What is Anaplastic carcinoma of the thyroid?

Answer 15

• undifferentiated MALIGNANT tumor of thyroid.
• usually seen in ELDERLY.
• often invades local structures leading to DYSHPAGIA or RESPIRATORY compromise.
• may be positive for cytokeratin.
• RAS or PIK3 mutations.
• poor prognosis.

Question 16

Remember, what does anaplastic carcinoma mimic?

Answer 16

• Reidel Fibrosing Thyroiditis, but this would be in a YOUNG FEMALE.

Question 17

Do thyroid adenomas generally give rise to carcinoma?

Answer 17

• NO (unlike the GI tract).

Question 18

What is the most aggressive variant of Papillary carcinoma?

Answer 18

• Tall cell variant