Endo - Pathology (Thyroid)

Question 1

Compare/Contrast hypothyroidism and hyperthyroidism in terms of their 8 major sets of symptoms.

Answer 1

(1) HYPO: Cold intolerance (decreased heat production), HYPER: Heat intolerance (increased heat production) (2) HYPO: Weight gain, decreased appetite, HYPER: Weight loss, increased appetite (3) HYPO: Hypoactivity, lethargy, fatigue, weakness, HYPER: Hyperactivity (4) HYPO: Constipation, HYPER: Diarrhea (5) HYPO: Decreased reflexes, HYPER: Increased reflexes (6) HYPO: Myxedema (facial/periorbital), HYPER: Pretibial myxedema (Graves disease), Periorbital edema (7) HYPO: Dry, cool skin; coarse brittle hair, HYPER: Warm, moist skin; fine hair (8) HYPO: Bradycardia, dyspnea on exertion, HYPER: Chest pain, palpitations, arrhythmias, increased number and sensitivity of Beta-adrenergic receptors

Question 2

What are the following lab findings in hypothyroidism versus hyperthyroidism: (1) TSH (2) free T3 and T4 (3) Cholesterol?

Answer 2

(1) HYPO: High TSH (sensitive test for primary hypothyroidism), HYPER: Low TSH (if primary) (2) HYPO: low free T3 and T4, HYPER: High free or total T3 and T4 (3) HYPO: Hypercholesterolemia (due to low LDL receptor expression), HYPER: Hypocholesterolemia (due to high LDL receptor expression)

Question 3

What is the most common cause of hypothyroidism in idodine-sufficient regions?

Answer 3

Hashimoto thyroiditis

Question 4

What is Hashimoto thyroiditis, and what is its mechanism of damage?

Answer 4

An autoimmune disorder (anti-thyroid peroxidase, antithyroglobulin antibodies)

Question 5

With what HLA type is Hashimoto thyroiditis associated?

Answer 5

Associated with HLA-DR5

Question 6

For what condition does Hashimoto thyroiditis increase the risk?

Answer 6

Increased risk of non-Hodgkin lymphoma

Question 7

When might Hashimoto thyroiditis patients be hyperthyroid, and why?

Answer 7

May be hyperthyroid early in course due to thyrotoxicosis during follicular rupture

Question 8

What are 2 major histologic findings in Hashimoto thyroiditis?

Answer 8

Histologic findings: Hurthle cells, lymphoid aggregate with germinal centers

Question 9

Describe the thyroid upon physical exam in a Hashimoto thyroiditis patient.

Answer 9

Findings: moderately enlarged, NONTENDER thyroid

Question 10

What are 8 conditions/causes of hypothyroidism?

Answer 10

(1) Hashimoto thyroiditis (2) Congenital hypothyroidism (Cretinism) (3) Subacute thyroiditis (de Quervain) (4) Riedel thyroiditis (5) Iodine deficiency (6) Goitrogens (7) Wolff-Chaikoff effect (8) Painless thyroiditis

Question 11

What is another name for Congenital hypothyroidism? What is it, and what causes it?

Answer 11

Congenital hypothyroidism (Cretinism); Severe fetal hypothyroidism due to maternal hypothyroidsim, thyroid agenesis, thyroid dysgenesis (most common cause in US), iodine deficiency, dyshormonogenic goiter

Question 12

What are 6 physical exam/clinical findings of Congenital hypothyroidism (Cretinism)?

Answer 12

Findings: (1) Pot-bellied (2) Pale (3) Puffy-faced child with (4) Protruding umbilicus (5) Protuberant tongue and (6) Poor brain development; Think: “the 6 P’s”

Question 13

In the US, what is the most common cause of Congenital hypothyroidism (Cretinism)?

Answer 13

Thyroid dysgenesis (most common cause in US)

Question 14

What is another name for Subacute thyroiditis? What is it, and what condition does it often folow?

Answer 14

Subacute thyroiditis (de Quervain); Self-limited hypothyroidism often following a flu-like illness

Question 15

What does Subacute thyroiditis (de Quervain) have in common with Hashimoto thyroiditis in terms of its early presentation?

Answer 15

May be hyperthyroid early in course

Question 16

What is significant in the histology of Subacute thyroiditis (de Quervain)?

Answer 16

Histology: granulomatous inflammation

Question 17

What are 4 lab/clinical findings associated with Subacute thyroiditis (de Quervain)?

Answer 17

Findings: (1) high ESR (2) Jaw pain (3) Early inflammation (4) very TENDER thyroid; Think: “de querVAIN is associated with PAIN”

Question 18

What is a major way that Hashimoto thyroiditis and Subacute thyroiditis differ on physical exam?

Answer 18

Hashimoto thyroiditis: NONTENDER thyroid; Subacute thyroiditis: very TENDER thyroid

Question 19

What occurs in Riedel thyroiditis?

Answer 19

Thyroid replaced by fibrous tissue (hypothyroid).

Question 20

To where may the fibrosis in Riedel thyroiditis extend, and what condition does that mimick?

Answer 20

Fibrosis may extend to local structures (e.g., airway), mimicking anaplastic carcinoma

Question 21

Of what disease is Riedel thyroiditis considered to be a manifestation?

Answer 21

Considered a manifestation of IgG4-related systemic disease

Question 22

What is the main clinical/physical exam finding in Riedel thyroiditis?

Answer 22

Findings: fixed, hard (rock-like, and PAINLESS goiter

Question 23

What are 3 types/causes of hyperthyroidism?

Answer 23

(1) Toxic multinodular goiter (2) Graves disease (3) Thyroid storm

Question 24

What defines toxic multinodular goiter, and what causes it?

Answer 24

Focal patches of hyperfunctioning follicular cells working independently of TSH due to mutation in TSH receptor

Question 25

What effect does toxic multinodular goiter have on thyroid hormone levels?

Answer 25

Increase release of T3 and T4

Question 26

Comment on the malignancy of hot nodules in Toxic multinodular goiter.

Answer 26

Hot nodules are rarely malignant

Question 27

What is Jod-Basedow phenomenon? With what thyroid condition is it associated?

Answer 27

Jod-Basedow phenomenon - Thyrotoxicosis if a patient with iodine deficiency goiter is made replete; Toxic multinodular goiter

Question 28

What is the most common cause of hyperthyroidism?

Answer 28

Graves disease

Question 29

What causes/defines Graves disease, and on what 3 locations does it act? What symptoms relate to each of these locations?

Answer 29

Autoantibodies (IgG) stimulate (1) TSH receptors on thyroid (hyperthyroidism, diffuse goiter), (2) Retro-orbital fibroblasts (exophthalmos: proptosis, extraocular muscle swelling), and (3) Dermal fibroblasts (pretibial myxedema)

Question 30

In what context does Graves disease often present? Give an example.

Answer 30

Often presents during stress (e.g., childbirth)

Question 31

What causes a thyroid storm, and what is it?

Answer 31

Stress-induced catecholamine surge seen as a serious complication of Graves disease and other hyperthyroid disorders

Question 32

What are 6 signs/symptoms in the presentation of thyroid storm? Which is a cause of death?

Answer 32

Presents with (1) agitation (2) delirium (3) fever (4) diarrhea (5) coma (6) tachyarrhythmia (cause of death).

Question 33

What is a significant lab finding that may be seen in thyroid storm, and what causes it?

Answer 33

May see high ALP due to increased bone turnover

Question 34

How is thyroid storm treated?

Answer 34

Treat with the "3 P's": beta-blockers (e.g., Propranolol), Propylthiouracil, corticosteroids (e.g., Prednisolone)

Question 35

What may be seen on histology of mulitnodular goiter?

Answer 35

Follicles of various sizes distended with colloid and lined by flattened epithelium with areas of fibrosis and hemorrhage

Question 36

Describe the physical exam finding of exophthalmos in a Graves disease patient.

Answer 36

Patient with bilateral proptosis and eyelid retraction. Visible sclera causes appearance of a "stare".

Question 37

What is the treatment option for thyroid cancers? What other thyroid condition can also use this treatment?

Answer 37

Thyroidectomy is treatment option for thyroid cancers and hyperthyroidism

Question 38

What are 3 complications of thyroidectomy? Where applicable, explain the cause.

Answer 38

Complications of surgery include (1) hoarseness (due to recurrent laryngeal nerve damage), (2) hypocalcemia (due to removal of parathyroid glands), and transection of inferior thyroid artery

Question 39

What are 5 types of thyroid cancer?

Answer 39

(1) Papillary carcinoma (2) Follicular carcinoma (3) Medullary carcinoma (4) Undifferentiated/Anaplastic carcinoma (5) Lymphoma

Question 40

What is the most common thyroid cancer? What kind of prognosis does it have?

Answer 40

Papillary carcinoma; Most common, excellent prognosis

Question 41

What are 3 histologic findings that characterize papillary carcinoma of the thyroid?

Answer 41

(1) Empty-appearing nuclei ("Orphan Annie" eyes) (2) Psammoma bodies (3) Nuclear grooves

Question 42

What are 3 risk factors for papillary carcinoma of the thyroid?

Answer 42

Increase risk with RET and BRAF mutations, childhood irradiation

Question 43

What kind of prognosis does Follicular carcinoma of the thyroid have?

Answer 43

Good prognosis

Question 44

How is Follicular carcinoma distinguished from Follicular adenoma of the thyroid? Also, in one word, describe the follicles of Follicular carcinoma?

Answer 44

Invades thyroid capsule (unlike follicular adenoma), uniform follicles

Question 45

What is the cellular origin of Medullary carcinoma thyroid?

Answer 45

From parafollicular "C cells"

Question 46

What is produced by Medullary carcinoma of the thyroid?

Answer 46

Produces calcitonin

Question 47

What histologic finding defines Medullary carcinoma of the thyroid?

Answer 47

Sheets of cells in an amyloid stroma

Question 48

With what conditions is Medullary carcinoma of the thyroid associated, and what mutation causes these?

Answer 48

Associated with MEN 2A and 2B (RET mutations)

Question 49

What patient population is (mostly) affected by undifferentiated/anaplastic carcinoma?

Answer 49

Older patients

Question 50

To what extent does Undifferentiated/Anaplastic carcinoma grow? What is its prognosis?

Answer 50

Invades local structures, very poor prognosis

Question 51

With what thyroid condition is lymphoma associated?

Answer 51

Associated with Hashimoto thyroiditis