Thyroid Pathology- Hunt

Question 1

What are three diseases that cause thyroid inflammation?

Give the eponymous names and the clinical names

Answer 1

1. Subacute granulomatous thyroiditis
   
   • de Quervain thyroiditis
2. Chronic Lymphocytic thyroiditis
   
   • Hashimoto’s thyroiditis
3. Fibrosing thyroiditis
   
   • Riedel thyroiditis

Question 2

What is the pathology behind Hashimoto’s thyroiditis?

What tests can confirm the diagnosis?

Answer 2

It is an autoimmune disease that produces auto-antibodies

Tests for anti-TPO and anti-Tg

Question 3

What does the thyroid look like grossly in hashimoto’s thyroiditis?

What does the thyroid look like on histology?

Answer 3

Diffuse enlargment

Thyroid will show lymphocyte infiltration and formation of germinal centers. Hurthle cells (large, pink) will also be found.

Question 4

What is the pathology behind subacute thyroiditis (de Quervain thyroiditis)?

What does the progression of the disease look like?

Answer 4

Unknown, but it is believed to be related to viral or post-viral states.

Painful, but self-limited

Question 5

What does de Quervain thyroiditis look like on histology?

Answer 5

Lots of neutrophil infiltrate

Giant cell granulomas

Question 6

What is the pathology behind fibrous thyroiditis (Riedel thyroiditis)?

What causes fibrous thyroiditis?

Answer 6

Thyroid tissue is replaced by collagen fibers and undergoes fibrosis.

unknown

Question 7

How is fibrous thyroiditis treated?

What complications can be seen in fibrous thyroiditis?

Answer 7

prednisone or surgery in some cases

tracheal compression, fibrous infiltration of surrounding structures

Question 8

What causes Grave’s disease?

What is seen on histology and what is seen grossly?

Answer 8

Antibodies activate the TSH receptor on the thyroid, causing hyperthyroidism.

Grossly, the thyroid will look larger. On histology, there will be scalloped colloid and irregular follicles.

Question 9

Very generally, what is a goiter?

What can cause a goiter?

Answer 9

An enlargment of the thyroid gland

Iodine deficiency (most common cause world wide)

Graves disease (most common in US)

Cyanide poisoning

Question 10

What does a goiter look like on histology?

What is the long term result of a goiter?

Answer 10

Variably sized follicles lined by columnar cells, with lots of colloid

With time, the goiter can degenerate into a cyst, fibrosis, calcification, or hemorrhage

Question 11

A patient comes into the clinic and had a nodule on her thyroid.

What is the likelihood that it is cancer?

What test should be done?

Answer 11

Very slim; carcinomas are >1% of nodules. It is more likely a cyst, hyperplasia, or benign tumor.

Fine needle aspiration should be done; it is useful for diganosing most carcinomas, but can not differentiate follicular adenoma from follicular carcinoma.

Question 12

Will follicular adenoma produce thyroid hormone?

Will follicular adenoma progress to carcinoma?

What does a follicular adenoma look like on histology?

Answer 12

Probably not, but some do

No, it is completely benign

It is surrounded by a fibrous capsule and will not invade surrounding tissue.

Question 13

How common is thyroid carcinoma?

What is the biggest risk factor?

Answer 13

Very rare; 1.5% of cancers

Exposure to ionizing radiation (huge spikes in thyroid cancer after cherynoble)

Question 14

What are the four different types of thyroid carcinoma?

What mutations are seen in each type?

Answer 14

1. Follicular
   
   • RAS mutation- constituitive growth
2. Papillary
   
   • BRAF/RAS- constituitive growth
3. Medullary
   
   • RET- activation of neuroendocrine receptor
4. Anaplastic
   
   • P53 mutation- cell can noot be killed, very aggressive tumor

Question 15

Who is most likely to get papillary thyroid cancer?

What might indicate a less favorable prognosis?

Answer 15

Young adults 20-40

patient older than 40

tumor larger than 5cm

extrathyroid extension

metastasis to bone

Question 16

What does papillary carcinoma look like on histology?

Answer 16

• Clear nuclei (orphan annie eyes)
• intranuclear inclusions
• intranuclear grooves

Question 17

Who is most likely to get follicular thyroid carcinoma?

What are signs of a less favorable prognosis?

Answer 17

patients ago 40-50

more advanced stage

Question 18

What does follicular carcinoma look like on histology?

Answer 18

Very well-differentiated; almost impossible to differentiate from follicular adenoma

However, capsular invasion or vascular invasion indicate follicular carcinoma.

Question 19

What is different between papillary and follicular carcinoma metastasis?

Answer 19

• Spread
  
  • Papillary spreads via the lymphatics while follicular spreads vascularly
• Prognosis
  
  • papillary carcinoma typically presents with metastasis, but survival is not affected; follicular survival is largely dependent on stage

Question 20

Medullary Carcinoma

Why does the mutation make sense?

What percentage of these tumors are sporadic and what percentage are due to a germline mutation?

Answer 20

RET is a signalling protein for neuroendocrine cells and medullary carcinoma affect parafollicular C cells.

80% are sporadic

20% are due to MEN-2

(on the brightside, you’d be protected against hirschprung’s with this mutation)

Question 21

What is seen on histology in a medullary carcinoma of the thyroid?

Answer 21

Nests of neuroendocrine cells

amyloid stroma- this is highly indicative and will usually be stained with congo red

Calcitonin +

Thyroglobulin -

Question 22

Who is most likely to get anaplastic thyroid carcinoma?

What is the prognosis?

What is seen on histology?

Answer 22

older adults (mean age of 65)

very bad; virtually 100% mortality

Nasty stuff, very ugly, very pleomorphic