Introduction to Thyroid Pathology Flashcards
What is a primary endocrinopathy?
Thyroid disorder
What is a secondary endocrinopathy?
Pituitary disorder
What is a goiter?
State of enlargement of the thyroid gland
What are Goitrogens?
Chemical agents that suppress thyroid function
What are C cells?
Parafollicular cells
What do parafollicular (C cells) release?
Calcitonin
Where are parafollicular cells located?
Within the wall of follicles around follicular cells
What is a medullary thyroid carcinoma?
Parafollicular neoplasm
What occurs in medullary thyroid carcinoma?
Increased serum calcitonin
What is thyrotoxicosis?
Hyperthyroidism
What can occur in hyperthyroidism in patients with underlying heart issues?
Low-output hear failure due to dilated cardiomyopathy (left ventricle too dilated so not large ejection fracture)
What occurs with lid lag?
Superior tarsal muscle pulls the lid too high so eyes appear to bulge but are not
What is true thyroid ophthalmopathy associated with?
Grave’s disease
What is cretinism?
Low iodine levels due to insufficient levels in diet; early childhood or mothers diet
What diseases can occur due to hypothyroidism?
Cretinism
Myxedema
Three differential diagnosis of goiters?
Inflammatory or immune-mediated disease
Non-neoplastic parenchymal enlargement
Neoplasms
What is the most useful screening test for hyper and hypothyroidism?
TSH levels
TSH levels in hyper:
Low (due to T4/T3 feedback to decrease release)
TSH levels in hypo:
High (no T3/T4 to turn it off)
What do hot nodules show?
Activity in thyroid
What do cold nodules show?
Inactivity due to neoplasms
Four thyroid disease categories:
Thyroiditis
Graves disease
Diffuse and Nodular goiter
Neoplasm
Four types of thyroiditis:
Hashimoto thyroiditis
Subacute lymphocytic thyroiditis
Granulomatous thyroiditis
Reidel thyroiditis
What is Hashimoto thyroiditis?
Hypothyroidism where iodine levels are sufficient
What type of goiter does Hashimoto cause?
Painless symmetric and diffuse
What causes Hashimoto thyroiditis?
Autoimmune disease with destruction of thyroid gland
Why can Hashimoto initially present as hyperthyroidism?
Inflammatory destruction of epithelial cells causing a spillage of T3/T4
What cells can be found in Hashimoto thyroiditis?
Hurthle cells
What is Subacute lymphocytic thyroiditis?
Autoimmune disease against antithyroid peroxidase
What is the goiter in Subacute lymphocytic thyroiditis?
Painless
What is a variant of Subacute lymphocytic thyroiditis?
Post-partum thyroiditis
What is granulomatous thyroiditis?
Most common cause of thyroid pain; self-limiting; transient inflammation
What does granulomatous thyroiditis cause?
Hyperthyroidism from destruction of cells and T3/T4 release
What occurs to iodine uptake in granulomatous thyroiditis?
Decreased radioactive iodine uptake
What occurs in Reidel thyroiditis?
Extensive fibrosis; maybe associated with pathologic progressive fibrosis
How is the thyroid seen in Reidel thyroiditis?
Hard and fixed thyroid that mimics carcinoma
What causes Graves disease?
Antibodies against the TSH receptors thus stimulating the receptors
What are the underlying cause of Graves disease?
Thyroid stimulating immunoglobulins (TSI)
What triad characterizes Graves disease?
Thyrotoxicosis
Ophthalmopathy
Dermopathy
What are the three types of goiters?
Diffuse (simple)
Multinodular
Dyshormonogenetic
What characterizes a diffuse goiter?
Uniform enlargement; TSH elevated but person is euthyroid
Two types of diffuse goiters?
Endemic goiter
Sporadic goiter
What causes endemic goiters?
Goitrogens or low iodine
What causes sporadic goiters?
Young people with unknown cause
Diffuse goiter pathology?
None it is non-toxic
What characterizes a multinodular goiter?
Numerous discrete nodules
Symptoms of multinodular goiters?
Most are euthyroid or can develop autonomous nodules that produce excessive thyroid hormones
What is dyshormonogenetic goiter?
Rare but familial goiter
What are the general statistics of thyroid neoplasms?
Solitary are more likely to be neoplastic
Nodules in younger patients and males are more likely to be neoplastic
Hot nodules are more likely to be benign than malignant
Four major types of carcinomas:
Papillary carcinoma
Follicular carcinoma
Anaplastic carcinoma
Medullary carcinoma
Papillary carcinoma:
85% of cases; Tend to metastasize to cervical nodes
Follicular carcinoma:
5-15% of cases; Capsular invasion or vascular invasion by neoplastic cells
Anaplastic carcinoma:
5% of cases; Aggressive 100% mortality
Medullary carcinoma:
Neuroendocrine carcinoma
C cells secretes calcitonin
Two phases of diffuse goiter?
Hyperplastic: Response to demand for more thyroid hormone
Colloid involution: Less demand for thyroid hormone
