Pathology of the Thyroid Flashcards
What is the cause of primary and secondary hyperthyroidism?
Primary = the thyroid gland itself is over-functioning Secondary = thyroid is overstimulated by TSH
What is tertiary hyperthyroidism?
Too much TSH because there is too much hypothalamic TRH
What is lid lag, and what disease is it seen in?
A delay in the downward movement of the upper eyelid as the patient looks down
Grave’s disease
What cardiac arrhythmia develops from hyperthyroidism?
A-fib
What type of autoantibody is directed against the thyroid gland in Graves’ disease? What specific part of the thyroid is this directed against?
IgG against the TSH receptor (also known as thyroid stimulating autoantibodies, TSAb)
What is the ratio of female:male incidence of Graves’ disease?
5:1
What are the T3/T4 and TSH levels in Graves’ disease?
High T3/T4
Low TSH
What causes the proptosis/exophthalmos in Graves’ disease?
Excess collagen/ground substance deposition behind the eyes, and antibodies directed against the eye muscles and fibroblasts behind the eye
Who usually exhibits pretibial myxedema: hyper or hypothyroid patients? How can you tell the difference?
Usually hypothyroid patients, but can occur with hyperthyroid states as well (e.g. Graves’ disease).
If in hyperthyroid states, usually confined to the shin area, and have nodules
What are the gross characteristics of the thyroid glad with Graves’ disease?
Diffuse, beefy red gland that is symmetrical
What are the histological characteristics of Graves’ disease? (2)
Hyperplasia of the follicles with papillary infoldings
Scalloping of the colloid
Down syndrome patients are more predisposed to developing what thyroid pathology?
Lymphocytic thyroiditis, with eventual hypothyroidism
What is myxedema?
Accumulation of hydrophilic ground substance throughout the connective tissue of the body
What gross PE findings can be found in patients with myxedema?
Coarsening of facial features
Macroglossia
Exophthalmos
Deepening of the voice
What are the distinctive facial features of Cretinism? (5)
Facial swelling Puffy eyelids Low hair line Protruding tongue Altered eyebrows
What is the natural h/o cretinism? Does replacing thyroid hormone later in the disease process reverse the ssx?
Small stature and MR.
Will not reverse the ssx, but will help
When is it necessary to begin treating cretinism to prevent the development of cretinism?
Before the 3rd week
True or false: in the US, all babies are screened for hypothyroidism
True
Which gender is usually affected with Hashimoto thyroiditis?
Female adults
What causes Hashimoto’s thyroiditis?
Deficiency in Tregs, causing an increase in CTLs and activated B cells
What is the HLA haplotype that is associated with the development of Hashimoto?
HLA-DR5
What are the gross findings of a thyroid with Hashimoto’s?
Diffusely enlarged thyroid with the capsule intact and well demarcated.
Cutting surface is pale, yellow-tan, firm
What causes the paleness of the thyroid in Hashimoto’s?
Infiltration of WBCs
What are the histological characteristics of Hashimoto’s?
Mononuclear inflammatory infiltrates with well developed germinal centers
Thyroid follicles are atrophic and are lined in many areas by epithelial cells
What are Hurthle cells?
Large, eosinophilic cells with granule cytoplasm found in Hashimoto’s thyroiditis
What is De Quervain (subacute granulomatous) thyroiditis?
A thyroid viral infection that is transient and self limiting
What is the telltale sign of De Quervain (subacute granulomatous) thyroiditis?
Painful thyroid
Who usually gets De Quervain (subacute granulomatous) thyroiditis?
40-50 y/o females
What are the four most common viral causes of De Quervain (subacute granulomatous) thyroiditis?
- Mumps
- Adenovirus
- Echovirus
- Coxsackie
What are the histological findings of De Quervain (subacute granulomatous) thyroiditis?
Granulomas with giant cells, macrophages, lymphocytes and destroyed thyroid follicles
What happens to T3/T4 levels with De Quervain (subacute granulomatous) thyroiditis? TSH levels?
Increased T3/T4
Decreased TSH levels
What causes a goiter?
Inability of the thyroid to produce T3/T4 for some reasons leads to an increase in TSH levels, which stimulates the growth of the thyroid gland
What happens to goiter development over time?
Goes from smooth to nodular
What is the female:male ratio of goiter development?
8:1
What is the endemic cause of goiter development?
Low iodine levels
What are the goitrogenic foods? Why are these goitrogenic?
cabbage
Cauliflower
Brussel sprouts
Turnips
Have a substance that inhibits the production of T3/T4
How can you differentiate between a thyroid neoplasm from thyroid hyperplasia?
Neoplasms lack a capsule
What are the histological characteristics of a goiter?
- Colloid rich follicles of varying sizes, with flattened epithelium
- Hemorrhage
- Hemosiderin
- Calcification
What is the epithelium flattened with a goiter?
Increase in colloid
What are “cold” nodules in goiters?
Nodules that fail to take up iodine during a nuclear scan
What are “hot” nodules in the thyroid?
Nodules that take up iodine during a nuclear scan
True or false: both benign and malignant thyroid conditions can cause a cold area on a thyroid scan
True
What is the only way to obtain a biopsy of the thyroid gland?
Fine needle aspiration (FNA)
Neoplastic thyroid nodules are generally hot or cold? What is the definitive way to diagnose this?
Usually cold, but only way to diagnose is biopsy with FNA
Who usually gets thyroid adenomas? What is the chance of a thyroid adenoma turning into a malignant mass?
Adult females
Extremely low chance of becoming malignant
What are the typical gross characteristics of a thyroid adenoma?
Spherical encapsulated lesion that is demarcated from the surrounding thyroid parenchyma by a well-defined, intact capsule
What are the four types of thyroid cancer in descending order of incidence?
Papillary
Follicular
Medullary
Anaplastic
What is the prognosis of a papillary thyroid cancer?
Good
What is the prognosis of a anaplastic thyroid cancer?
Very bad
What is the prognosis of a follicular thyroid cancer?
50% survival
What is the prognosis of a medullary thyroid cancer?
50% 5 year mortality
What is the most common reason for the development of papillary thyroid carcinoma?
Irradiation of the thyroid
What is the risk of developing papillary carcinoma of the thyroid with radioablation of the thyroid?
Very small
What are the gross and histological characteristics of papillary thyroid carcinoma?
Gross = fibrovascular stalk with tumor cells Histo = Orphan annie eye nuclei
What are the Orphan Annie eyed nuclei found in papillary thyroid carcinoma?
Margination of the chromatin d/t fixation
Nuclear grooves (AKA coffee bean nuclei) = ?
Papillary thyroid carcinoma
Psammoma bodies in the thyroid are indicative of what pathological process?
Papillary thyroid carcinoma
Nuclear hole in thyroid = ?
Papillary thyroid carcinoma
What are the gross and histological characteristics of follicular thyroid carcinoma?
Gross = gray-tan, single encapsulated nodule with fibrosis, calcification
Histological = Hurthle cells in follicular pattern
Why is the prognosis of follicular carcinoma worse than papillary? What is odd about this cancer?
has a higher rate of metastases
Does not met to the lymph—hematogenous spread
What is the familial disorder that predisposed patients to the development of medullary thyroid carcinoma? What is the genetic defect in this disease?
MEN2
RET gene on chromosome 10
What are the cells that are defective in medullary thyroid CA?
C cells
What are the gross and histological features of medullary thyroid CA?
Gross = nonencapsulated mass(es)
Histological = Amyloid stroma
What does anaplastic carcinoma of the thyroid usually arise from?
Previous papillary or follicular thyroid CA
What are the histological characteristics of anaplastic thyroid CA?
Highly anaplastic cells with cytokeratin but TG -
Large giant cells
