Thyroid Pathology

Front 1

What is this?

Back 1

Normal Thyroid and parathyroid!

Front 2

Explain NORMAL embryological development of the Thyroid Gland.

Where does it originate?

Back 2

The Thyroid gland originates at the base of the tongue and extends down the to the anterior neck. The duct which goes down gets involuted (deleted).

Front 3

What is Thyroglossal Duct Cyst?

Where does the mass appear?

Back 3

The duct is the connection from where the Thyroid began developing (base of tongue) to its final location (anterior neck)

The duct fails to involute (delete) during development. A persistent duct may undergo cystic dilation

Anterior Neck mass

Front 4

What is Lingual Thyroid?

Back 4

Persistence of the thyroid at the base of the tongue (doesn't extend down).

Presents as a base of tongue mass

Front 5

Basic principles of Hyperthyroidism? (2 things it increases and MOA)

Back 5

Increased basal metabolic rate (increased Na/K ATPase synthesis)

Increases sympathetic nervous system (Increased in beta receptor)

Front 6

Common symptoms of hyperthyroidism?

Back 6

Weight loss, despite increased appetite
Heat intolerance, sweating
tachycardia
arrhythmia
Diarrhea
Bone resoprtion (osteoporosis)
Hypocholesterolemia
Hyperglycemia (gluconeogensis and glycongenolysis)

Front 7

What is Grave's Disease?

Back 7

IgG autoantibody that stimulates TSH receptor (type II hypersensitivity)

Increased synthesis and release of thyroid hormone

Most common cause of hyperthyroidism

Women of childbearing age: most common group

Front 8

What is the most common cause of hyperthyroidism?

Back 8

Grave's Disease

Front 9

What type of hypersensitivity reaction is Grave's disease?

What type of autoantibody?

Back 9

Type II

IgG

Front 10

Clinical features of Grave's disease

Back 10

Hyperthyroidism

Diffuse goiter

Exophthalmos (bulging of the eye anteriorly)

Pretibial myxedema-nonpitting scaly thickening and induration of the skin

Front 11

Common symptoms of Grave's disease?

Back 11

Weight loss, despite increased appetite
Heat intolerance and sweating
Tachycardia
Arrhthmia
Diarrhea
Hypocholesterolemia
Hyperglycemia

Front 12

What is diffuse goiter?

Back 12

Diffuse goiter is the enlargement of the thyroid in a diffuse manner.

(due to hyperplasia and hyperthrophyy of thyroid due to overstimulation by "TSH")

Front 13

MOA behind Exophthalmos and pretibial myxedema

Back 13

Fibroblasts behind the orbit and shin express TSH receptor

TSH activation results in glycosaminoglycan buildup leading to inflammation, fibrosis and edema

Front 14

What molecule/material builds up in Exophthalmos and pretibial myxedema?

What is it stimulated by?

Back 14

Glycosaminoglycan

Stimulated by TSH

Front 15

What is this?

Back 15

Diffuse Goiter

(Would also see chronic inflammation)

Front 16

Lab findings of Grave's disease? (4)

Back 16

Increased total and free T4.
Decreased TSH

Hypocholesterolemia
Hyperglycemia

Front 17

What is the most fatal complication of Grave's disease?

Back 17

Thyroid storm!

Front 18

What is thyroid storm?

When does it occur?

Symptoms?

Back 18

Fatal complication of Grave's disease.

Too much catecholamines (sympathetic) in response to stress (injury, surgery, birth, etc.)

Presents as arrhthymia, hyperthermia, vomiting, hypovolumic shock

Front 19

What is Multinodular goiter?

Etiology?

Consequences?

Back 19

Enlargement of thyroid with multiple nodules

Due to decrease iodine

Usually nontoxic (euthyroid - "normal" thyroid)

Rarely, toxic goiter

Front 20

What is toxic goiter?

Back 20

Rare consequence of multinodular goiter.

Regions become TSH independent leading to hyperthyroidism (release on their own)

Front 21

Common symptoms of hypothyroidism?

Back 21

All due to decreased metabolic rate and decreased sympathetic nervous system.

Weight gain, despite normal appetite
Cold intolerance
Constipation
Bradycaria
Hypercholesterolemia
Myxedema (due to glycosaminoglycans in skin)

Front 22

Cretinism vs. Myxedema

(age group?)

Back 22

Cretinism - hypothyroidism in neonates + infants

Myxedema - hypothyroidism in older children + adults

Front 23

Cretinism

Common symptoms

Back 23

Hypothyroidism in neonates + infants

Mental retardation, short stature with skeletal muscle abnormality, weird facial features, enlarged tongue, and umbilical hernia

Thyroid needed for brain + skeletal development

Front 24

Etiology of Cretinism

Back 24

Maternal hypothyroidism during pregnancy

Thyroid agenesis

Iodine deficiency

Dyshormonogenetic goiter - congenital defect in thyroid hormone production

Front 25

Myxedema

Common symptoms?

Back 25

Hypothyroidism in older children and adults

All due to decreased metabolic rate and decreased sympathetic nervous system.

Weight gain, despite normal appetite
Cold intolerance
Constipation
Bradycaria
Hypercholesterolemia
Myxedema (due to glycosaminoglycans in skin)

Front 26

Etiology of Myxedema

Back 26

Most common causes: iodine deficiency and Hashimoto thyroiditis

Other causes: drugs (lithium), surgical removal, radioablation of thyroid

Front 27

What are the most common causes of Myxedema?

Back 27

Iodine deficiency and Hashimoto Thyroiditis

Front 28

What is Hashimoto thyroiditis?

Associated with what HLA?

Most common cause of hypothyroidism in regions where ___________ are adequate

Back 28

Autoimmune destruction of the thyroid glands

Associated with HLA-DR5

Most common cause of hypothyroidism in regions iodine levels are adequate

Front 29

Clinical features of Hashimoto thyroiditis

Back 29

Hyperthyroidism initially b/c all the stored thyroid all thrown out due to follicle damage

Progresses to hypothyroidsm (low T4, high TSH)

Antithyroglobulin and antimicrosomal antibodies (they aren't the cause; MARKERS)

Front 30

name 2 antibody markers for Hashimoto thyroiditis

Back 30

Antithyroglobulin and antimicrosomal antibodies

Front 31

Is there an initial increase or decrease in thyroid in Hashimoto thyroiditis? Why?

Back 31

Increase b/c the damage follicle cells release all the stored thyroid

Front 32

Common histological finding of Hashimoto thyroiditis?

Back 32

Chronic inflammation with germinal centers and Hurthle cells (eosophillic aka PINK)

Front 33

What are Hurthle cells?

Associated with what disease?

Back 33

Eosinophilic metaplasia of cells that line follicles

Associated with Hashimoto thyroiditis

(normally NOT pink)

Front 34

What are you at an increased risk of if you have Hashimoto Thyroiditis (what cancer?)

Back 34

B-cell (marginal zone) lympoma

presents as an enlarged thyroid gland then

Front 35

Subacute Granulomatous (De Quervain) Thyroiditis

Prognosis?

Back 35

Granulomatous thyroiditis that follows a viral infection

Presents as a TENDER* thyroid with transient hyperthyroidism

Self-limited (doesn't progress to hypothyeroidsm)

Front 36

What is tender thyroid associated with?

Back 36

Subacute thyroiditis

Front 37

Reidel Fibrosing Thyroiditis

Back 37

Chronic inflammation with extensive fibrosis of the thyroid gland

"hard as wood" nontender thyroid gland with hypothyroidism

Fibrosis may extend to involve local structures (airway, esophagus); mimics anaplastic carcinoma but these pt. are YOUNGER

Front 38

What does Reidel Fibrosing Thyroiditis mimic?

How do you differentiate?

Back 38

Mimics anaplasic carcinoma

But RFT pt. are younger and on biopsy don't have malignant cells

Front 39

What is "hard as wood non tender thyroid gland" associated with?

Back 39

Reidel fibrosing thyroiditis?

Front 40

Why might you get Dysphagia and trouble breathing with Reidel fibrosing Thyroiditis?

Back 40

The fibrosing may spread from the thyroid to nearby structures

Front 41

Thyroid Cancers

Basic principles
- multiple or solitary nodules?
-Most benign or malingant?

Back 41

Usually presents as a distinct solitary nodule
Most are benign

Front 42

What studies are used to further characterize a nodule?

Back 42

Radioactive Iodine (131) uptake studies

Front 43

Increased uptake of iodine on radioactive uptake studies suggests what diseases?

Back 43

Suggests grave's disease or nodular goiter
('hot nodules b/c hyperthyroidism)

Front 44

Decreased uptake of Iodine on radioactive uptake studies suggest what diseases?

What is the next step?

Back 44

CANCERs

Adenoma and carcinoma

BIOPSY!

Front 45

When should you biopsy? (increased or decreased uptake of Iodine in radioactive uptake studies?)

What kind of bioposy?

Back 45

Decreased uptake MAY indicate cancer thus biopsy!

Fine needle aspiration biopsy!

Front 46

Follicular adenoma

Functional or non-functional?
Benign or malignant?

Back 46

Benign proliferation of follicles surrounded by capsule

Usually nonfunctional (doesn't secrete thyroid)

Front 47

What is this? How can you tell?

Back 47

Follicular adenoma

(looking at the picture, you can tell the top looks different from bottom. The seperation is the CAPSULE.)

Benign

Front 48

4 types of carcinomas of the Thyroid

Back 48

Papillary, Follicular, Medullary, Anaplastic

Front 49

How do MOST carcinomas spread?

(via blood or lymph node)

4 common exceptions?

Back 49

MOST spread via lymph nodes

Renal cell carcinoma, hepatocellular carcinoma, choriocarcinoma, follicular carcinoma are the exception!

Front 50

What is the most common type of thyroid carcinoma?

Back 50

Papillary carcinoma

Front 51

Papillary carcinoma

Risk factor/Etiology?
Appearance (histology)
Spread where?
Prognosis?

Back 51

Most common type of thyroid carcinoma

Risk factor: exposure to ionizing radiation in childhood

Histology: 'Orphan Anni eye nuclei'
nuclear grooves
associated with psammoma bodies

Spread to cervical lymph nodes
GREAT prognosis

Front 52

What is this (the white clearing in the nucelus)?

Associated with what disease?

Back 52

Orphan Annie eye nuclei (clear white in nucleus)

Seen in Papillary carcinoma (all types including Thyroid)

Front 53

What are Psammoma bodies?

Back 53

Round collection of calcium seen microscopically

(picture shows Papillary carcinoma of the kidney. But just shows you psamma bodies!)

Front 54

Follicular Carcinoma

Benign or Malignant?
It is an exception to what rule?

Back 54

Malignant proliferation of follicles surrounded by capsule but this INVADES past the capsule

Exception to the rule that carcinomas spread via lymph nodes. This spreads via BLOOD.

Front 55

What is the difference b/w follicular carcinoma and adenoma?

Can Fine needle aspiration help distinguish?

Back 55

Adenoma doesn't invade pass the capsule

FNA only examines cells and not the capsule thus it doesn't help you distinguish the difference

Front 56

Medullary carcinoma

Benign or malignant?
Histology?
Genetics?

Back 56

Malignant proliferation of C cells

Histology: sheets of malignant cells in an amyloid stroma

If it is genetic then it is related to multiple endocrine neoplasia (MEN 2A and 2B)
These are associated with mutations in RET oncogene

Front 57

What to do with thyroid if RET mutation found?

Back 57

Prophylacit thyroidectomy

Front 58

What is the role of C cells? What is the role of its product released?

What does calcitonin deposit within the tumor as?
What cancer causes proliferation of C cells?

Back 58

C cells produce calcitonin
Calcitonin decreased calcium

Calcitonin depositins within the tumor as amyloid

Medullary Carcinoma

Front 59

Calcitonin

Back 59

Decreases calcium

Hypocalciemia

Front 60

Anaplastic Carcinoma

What age group?

What can it be confused with? How do you differentiate?

Prognosis?

Back 60

Undifferentiated malignant tumor of the thyroid

Seen in elderly

Can be confused with Reidel Fibrosing Thyroditis (age + biopsy differ b/w the two)

Invades local structures such as esophagus and throat

Poor prognosis