Thyroid Pathology - Krafts Flashcards
What two effects does TSH have on the thyroid?
Thyroid growth and Hormone synthesis
What are the two thyroid lab tests are the most important?
TSH and T4
Labs in Primary Hyperthyroidism?
High T4 + Low TSH
Labs in Secondary or Tertiary Hyperthyroidism?
High T4 + High TSH
Labs in Primary Hypothyroidism?
Low T4 + High TSH
Labs in Secondary or Tertiary Hyperthyroidism?
Low T4 + Low TSH
Labs in Subclinical Hyperthyroidism?
Normal T4 + Low TSH
Labs in Subclinical Hypothyroidism?
Normal T4 + High TSH
What are the other less common/less important thyroid lab tests?
Free T3
Antibody tests => anti-peroxidase Ab (Hashimoto), anti-thyroglobulin Ab (Hashimoto/Grave’s), anti-TSH receptor Ab (Grave’s)
Radioiodine scanning
What kind of problems give rise to Primary, Secondary, and Tertiary Hyperthyroidism/Hypothyroidism?
1°: thyroid problem
2°: pituitary problem
3°: hypothalamic problem
What are the signs and symptoms of Hyperthyroidism?
General: weight loss, heat intolerance
Cardiac: rapid pulse, arrhythmias
Neuromuscular: tremor, emotional lability
Skin: warm, moist
Gastrointestinal: diarrhea
Eye: lid lag (eye lid does not move with eye movement due to increased sympathetic stimulation of ocular muscles)
Thyroid storm: extreme, dangerous symptoms
What are the common and uncommon causes of Hyperthyroidism?
Common: Graves disease, Multinodular goiter, Thyroid adenoma
Uncommon: Thyroiditis, Drugs, Thyroid carcinoma, Pituitary adenoma, Struma ovarii (hamartoma on ovary), Factitous (taking thyroid hormone to lose weight)
What are the signs and symptoms of Hypothyroidism?
General: fatigue, weight gain, cold intolerance
Cardiac: slow pulse, impaired contraction
Nervous: delayed reflexes, lethargy
Skin: rough, dry; hair loss (outer 1/3 of eyebrows)
Gastrointestinal: reduced appetite, constipation
Myxedema: deepened voice, “edema” (firm ground substance in any tissues)
Myxedema coma: deteriorating mental status
What are the causes of Congenital Hypothyroidism?
iodine deficiency, genetic problems
Tx with thyroid hormone replacement
What are the common and uncommon causes of Acquired Hypothyroidism?
Common: Hashimoto, Iatrogenic
Uncommon: Goiter Infiltrative stuff Too much iodine 2° hypothyroidism 3° hypothyroidism Other thyroiditis
What are the four types of Thyroiditis?
- Hashimoto Thyroiditis (Mrs. Potatohead)
- DeQuervain Thyroiditis (Rex)
- Silent Thyroiditis (Bullseye)
- Reidel Thyroiditis (Woody)
What is Hashimoto Thyroiditis?
Autoimmune disease of thyroid (genetic predisoposition)
Painless, big thyroid
F»M
Eventual hypothyroidism
How do you diagnose Hashimoto Thyroiditis?
Thyroid function tests:
The usual 1° hypothyroidism findings(Low T4 + High TSH)
Anti-thyroid antibody tests:
Anti-peroxidase antibodies
What unique cells can be seen in Hashimoto Thyroiditis?
Hurthle Cells
What are the T-cell and B-cell consequences in Hashimoto Thyroiditis?
T cells are screwed up:
don’t recognize own thyroid antigens!, attack thyroid, stimulate B cells
B cells are unwitting accomplices
anti-TSH-receptor antibody, anti-thyroglobulin antibody, anti-peroxidase antibody
How does DeQuervain Thyroiditis present?
Big, sore thyroid => follicles burst open and release T3/T4
Recent URI
Suddenly/Early, hyperthyroidism
Self-limiting
What is the pathogenesis of DeQuervain Thyroiditis?
Viral infection initiates.
Antigen causes an increase in CD8 cells.
Damaged follicles leak colloid.
Foreign-body giant cell reaction ensues.
How does Silent Thyroiditis present?
Post-partum or middle age.
Painless, slightly enlarged thyroid.
Mild hyperthyroidism early on.
How does Reidel Thyroiditis (fibrosing thyroiditis) present?
Rare!
Rock-hard neck mass (feels like a stone)
Hypothyroidism
Tracheal compression
What is the most common cause of hyperthyroidism in the US?
Grave’s Disease
F>M
What three symptoms in the classic triad of Grave’s Disease?
Hyperthyroidism
Ophthalmopathy (exophthalmous, retro-orbital tissues)
Dermopathy (pre-tibial fibroblasts, thickening/discoloration of pre-tibial region)
What lab tests are used to diagnose Graves Disease?
What does the microscopic appearance of Graves Disease look like?
epithelial proliferation, papillae and scalloped colloid
What is the pathogenesis of Graves Disease?
anti-TSH-receptor antibodies
=> follicular cell proliferation => thyroid gets big
=> thyroid hormone release => sx of hyperthyroidism
What causes a Goiter? Pathogenesis?
Inflammatory (thyroiditis) or non-inflammatory (defective T4 synthesis)
defective enzymes/kale/cabbage/no iodine/? => ↓T4 => ↑TSH => Gland grows => GOITER!
What is the difference between a simple goiter and multinodular goiter?
Simple = enlarged thyroid
Multinodular = cycles of hyperplasia and involution of thyroid tissue with fibrous deposition
How do Thyroid neoplasms present?
Most neoplasms present as nodules.
Nodules are common!
Most are benign.
Thyroid carcinoma is uncommon.
What pt circumstances are more likely to be thyroid cancer?
It’s more likely to be cancer if:
- Patient is male
- Nodule is solitary
- Nodule is cold
- There is a history of radiation
What test can be done to take a small sample of the thyroid?
Thyroid fine needle aspiration
What is the clinical presentation/clinical findings in a patient with Thyroid Adenoma?
Common!
Most patients are euthyroid, Some hyperthyroid
What tests do you use to Dx a Thyroid Adenoma?
TSH and T4 usually normal
Radioiodine scan => Most adenomas “cold”
What is the morphology of Thyroid Adenomas?
Solitary
Encapsulated
No invasion
What are the unique genetic characteristics of Thyroid Adenomas?
May have G-protein mutation
Gain-of-function mutation
Why do you remove Thyroid Adenomas even though they are benign neoplasms?
Adenoma can look like carcinoma. Need to see whole capsule to tell the two apart.
What is the most common type of malignant Thyroid Carcinoma? Next common?
Papillary
Then follicular, medullary, and anaplastic
What type of malignant Thyroid Carcinoma has the best prognosis?
Papillary => Excellent prognosis (>95% 10y survival)
What patient population is Papillary Thyroid Carcinoma most common in?
F > M, 30s-50s
Where are the most common locations of metastases in Papillary Thyroid Carcinoma?
Local lymph node metastasis common
Visceral metastasis rare
What is the morphologic appearance of Papillary Thyroid Carcinoma?
“Trees with branches” Orphan Annie nuclei psammoma bodies pseudoinclusions nuclear grooves (look like coffee beans)
Why is Papillary Thyroid Carcinoma considered “The Little Orphan Annie Tumor”?
Often affects younger women
Tends to stay around for years => without getting any bigger
Is usually well-behaved; seldom kills people
Has nuclei that resemble Orphan Annie’s eyes
Has psammoma bodies (from the greek psammos, or sand) => Annie’s dog is named Sandy
What patient population are Follicular Thyroid Carcinomas most common in?
F > M, 40s-50s
What is the prognosis of Follicular Thyroid Carcinomas?
Mets, if present, are in lung or bone
95% 10y survival in young patient with small, minimally invasive tumor
Prognosis worsens with increasing age, tumor size, and invasiveness
What patient population are Medullary Thyroid Carcinomas most common in?
F>M, 50s-60s
What is Medullary Thyroid Carcinoma a malignancy of?
Uncommon malignancy of C cells
Sporadic (most) or familial
What is the prognosis of Medullary Thyroid Carcinoma?
90% 10y survival if confined to thyroid
20% 10y survival if distant mets are present
What does the morphology of Medullary Thyroid Carcinoma look like under microscope?
Amyloid deposition => pink bubble gum stretched out
Amyloid is apple green with Congo red stain
Salt & Pepper chromatin nuclei
What is the clinical presentation of Medullary Thyroid Carcinoma?
Rare
F>M, 50s-60s
Bulky, fast-growing, invasive neck mass
Usually metastatic at diagnosis
What is the prognosis of Medullary Thyroid Carcinoma?
Very bad prognosis (
What is the clinical presentation of Anaplastic Thyroid Carcinoma?
Rare
F>M, 50s-60s
Bulky, fast-growing, invasive neck mass
Usually metastatic at diagnosis
What is the prognosis of Anaplastic Thyroid Carcinoma?
Very bad prognosis (
