Pathology Of The Thyroid

Question 1

What are some disorders of the thyroid gland

Answer 1

Hyperthyroidism
●Hypothyroidism (Euthyroid)
●Thyroiditis
●Diffuse multinodular Goiter.
●Neoplasms – adenoma/carcinoma.
●Congenital – Thyroglossal cyst/duct.

Question 2

Give some causes for hyperthyroidism

Answer 2

Thyrotoxicosis – High T3/T4, low TSH
●Diffuse toxic hyperplasia (Graves)
●Toxic multinodular goitre
●Toxic adenoma
●Thyroiditis
●Functioning thyroid carcinoma
●TSH secreting pituitary adenoma

Question 3

What is Graves’ disease

Answer 3

Common (2%F)
●Females, 20-40y, Autoimmune.
●Triad of clinical features,
•Hyperthyroidism
•exophthalmos
•Pretibial myxedema.
●Ab to TSH receptor – LATS.
●Diffuse hyperplasia, tall columnar cells, papillary folds.
●Scalloped, pale, scanty colloid.

Question 4

What are some effects of hypothyroidism

Answer 4

Cretinism / Myxedema – Low T3/T4, High TSH

Question 5

What are some causes of hyperthyroidism

Answer 5

Hashimoto’s thyroiditis - autoimmune
●Iodine deficiency
●Drugs – iodides, lithium
●Developmental – Atrophy, hypoplasia Pituitary disorders
●Radiation/Surgery

Question 6

What are some clinical features of cretinism

Answer 6

Impaired cns & bone growth
●Mental retardation
●Short stature
●Coarse facial features
●Protruding tongue
●Umbilical hernia

Question 7

What are some clinical features of myxedema

Answer 7

Slow physical and mental activity
●Cold intolerance
●Over weight
●Low cardiac output
●Constipation and decreased sweating
●Cool pale thick skin

Question 8

What is Hashimoto thyroiditis

Answer 8

Common non endemic goitre.
●More common in females (45-65yr).
●Autoimmune HLA-DR5, DR3.
●Antithyroglobulin antibody
●Firm diffuse goitre.
●Follicle atrophy with lymphocytes.
●Hürthle cells – eosinophilic epithelial cells.
●Initial hyperthyroidism.
●High risk of B cell lymphoma

Question 9

What is granulomatous thyroiditis

Answer 9

Subacute or DeQuervain thyroiditis.
●Less common, Females, 30-60 years
●Pain, fever, fatigue, myalgia.
●Post viral syndrome.
●Genetic association - HLA B35
●Patchy microabscess, granulomas with giant cells.
●Hyperthyroidism.
●Heals with normal thyroid function.

Question 10

What is diffuse/multinodular goiter

Answer 10

Endemic & sporadic types
●Cassava – thiocyanate – iodide transport.
●Sporadic – rare, females, young.
●Hyperplastic stage & Colloid stage.
●Repeated attacks  multinodular.
●Hyperplasia, fibrosis, cystic, necrosis
●Mass effect, dysphagia, airway obstruction
●Rarely toxic hyperthyroidism plummer syndrome.

Question 11

What are neoplasms of the thyroid

Answer 11

Usually solitary, benign.
●Good prognosis - <1% cancer mort.
●May be functional – hot nodule.
●Malignancy - Infiltration – fixation, hoarseness, recurrent laryngeal nerve damage.

Question 12

Mention some neoplasms of the thyroid

Answer 12

Adenoma – Follicular adenoma
●Papillary Carcinoma – 75-80%
●Follicular carcinoma - 10-20%
●Medullary carcinoma – 5%
●Anaplastic carcinoma - <5%

Question 13

What is a thyroid adenoma

Answer 13

Follicular common, rarely Papillary
●Compact follicles (large in MNG)
●Solitary, rarely Functional or hot.
●Centre may show necrosis/hem.
●Well capsulated.
●Compressed normal gland.

Question 14

What is a thyroid carcinoma

Answer 14

●Uncommon in children, seen in elderly.
●Common - Papillary adenocarcinoma.
●Associated with radiation exposure.

Question 15

What is a papillary carcinoma

Answer 15

Most common cancer – 75-80%
•Idiopathic
•Associated with Radiation, Gardner & Cowden syndromes.
•Papillary folds, Psammoma bodies, Orphan-annie nucleus.
•98% 10year survival when localized.