Thyroid and Salivary Gland Pathology Flashcards (Video Notes)

A comprehensive set of Q&A flashcards covering thyroid hormone regulation, anatomy, imaging features, common diseases (Graves’, hyper-/hypothyroidism, goiter), parathyroid physiology and diseases, and salivary gland tumors with typical ultrasound characteristics.

What pituitary hormone regulates secretion of thyroid hormones?

Thyroid-stimulating hormone (TSH).

Which organs form the hypothalamic–pituitary–thyroid axis that maintains circulating T3 and T4?

Hypothalamus, pituitary gland, and thyroid gland.

Name the three major roles of thyroid hormones.

Development, growth, and metabolism.

On ultrasound, what is a common peripheral feature of hyperfunctioning thyroid adenomas?

A thin peripheral halo around the lesion (approximately 2–3 mm).

What is calcification along the rim of a thyroid nodule sometimes called, and what may accompany it?

Eggshell (rim) calcification; may be associated with posterior shadowing.

Can thyroid adenomas appear cystic or solid?

Yes. They can be cystic, solid, anechoic, or complex; most are solid but some may degenerate to cystic.

Are thyroid adenomas typically solitary or can they be multimodular?

Most are solitary but can be multimodular.

What hormones are secreted by the thyroid?

Thyroxine (T4), Triiodothyronine (T3), and Calcitonin.

What hormone is secreted by the parathyroid glands?

Parathyroid hormone (PTH).

Describe the normal appearance of the thyroid on sonography.

Granular, homogeneous parenchyma that is slightly more echogenic than surrounding muscles; smooth borders.

What are the typical size ranges for the thyroid gland? (length, AP height, width, isthmus)

Length 4–6 cm; AP height 1.3–1.8 cm; width 1.5–2 cm; isthmus 4–6 mm (slightly larger in females).

What does euthyroid mean?

Normal thyroid function.

List benign ultrasound criteria for thyroid nodules.

Smooth, well-defined oval/round shape; homogeneous texture; may be hypo- or hyperechoic; minimal blood flow; posterior enhancement; stable or slow growth; compressibility.

List malignant ultrasound criteria for thyroid nodules.

Irregular, poorly defined margins; heterogeneous; internal blood flow; posterior shadowing; rapid enlargement; fixed and rigid.

What is the normal range for TSH given in the notes?

3–30 ng/mL.

What are the ranges for T4 and T3 as given?

Free T4: 0.8–2.4 ng/dL; Total T4: 4–11 ng/dL; T3: 75–220 ng/dL.

What is the normal calcitonin level and its clinical significance?

Calcitonin < 100 pg/mL; higher levels are associated with medullary thyroid carcinoma.

What does athyrosis refer to?

Complete or partial absence of the thyroid gland.

What is a pyramidal lobe?

An anatomical variant extending upward from the thyroid isthmus.

What is non-toxic goiter?

Enlargement of the thyroid gland without functional disturbance, commonly due to iodine deficiency.

Define goiter.

Enlargement of the thyroid gland; may press on the esophagus or trachea; more common in women aged 30–50.

Which ultrasound features characterize Graves' disease?

Enlargement with homogeneous texture, hypoechoic appearance, and increased vascularity on color Doppler.

What distinguishes primary from secondary hyperthyroidism?

Primary: excess thyroid hormone produced by the thyroid gland itself; Secondary: excess TSH secretion from the pituitary.

List common signs and symptoms of hyperthyroidism.

Nervousness, increased appetite, sweating, palpitations, tachycardia, exophthalmos.

What are common causes of hypothyroidism according to the notes?

Defective hormone synthesis, iodine deficiency or excess, inflammatory conditions; secondary causes include pituitary/hypothalamic disorders or irradiation.

What are typical signs of hypothyroidism?

Thickened skin, weight gain/hair loss, lethargy/cold intolerance, constipation, decreased heart rate.

Which organs does PTH act on to regulate calcium?

Bone, kidney, and intestine.

What are the main parathyroid pathologies and their features?

Hyperparathyroidism (adenoma, hyperplasia, carcinoma); secondary hyperparathyroidism (chronic renal failure or Vitamin D deficiency).

Describe a parathyroid cyst.

Asymptomatic; painless movable neck lump; may cause hoarseness, dysphagia, and pain.

Which is the most common benign tumor of the parathyroid? What are its features in labs?

Parathyroid adenoma; causes hyperparathyroidism; labs show high calcium and often low phosphate.

Describe parathyroid carcinoma.

Malignant; infiltrates surrounding tissue; associated with hyperparathyroidism; labs show high PTH and high calcium.

Which thyroid cancer is the most common and has the best prognosis with early treatment?

Papillary carcinoma; often hypoechoic with microcalcifications and lymph node involvement.

What ultrasound features suggest papillary thyroid carcinoma?

Hypoechoic; microcalcifications; hypervascularity with disorganized vessels; cervical lymph node metastasis with punctate calcifications.

Which thyroid carcinoma spreads via the bloodstream and is usually solitary with a well-encapsulated appearance?

Follicular carcinoma.

What ultrasound features are associated with follicular carcinoma?

Irregular margins; thick irregular halo; nodular enlargement; internal blood vessels; capsule invasion in widely invasive cases.

Name a rare, aggressive thyroid cancer often arising in the setting of Hashimoto's thyroiditis.

Anaplastic thyroid carcinoma; presents as a large, solid, hypoechoic, lobulated mass; color Doppler may be nonvascular; may encase vessels.

What are ultrasound features of anaplastic carcinoma regarding vascularity and tissue involvement?

Often nonvascular on color Doppler; adjacent thyroid tissue may be heterogeneous; may rapidly obstruct airway.

In Hashimoto's disease, what are common ultrasound features and Doppler findings?

Diffuse, chronic lymphocytic thyroiditis with enlargement; often hypoechoic and heterogeneous; variable vascularity on color Doppler.

What is the percentage distribution of benign vs malignant tumors in salivary glands (major glands) according to notes?

Most tumors are epithelial; about 75% or less occur in the parotid; about 15% of parotid tumors are malignant; submandibular gland tumors are 40–60% malignant; sublingual gland tumors ~1% with ~90% malignant.

What is the most common benign salivary gland tumor?

Pleomorphic adenoma (mixed tumor).

Which is the most common malignant salivary gland tumor and where does it primarily occur?

Mucoepidermoid carcinoma; primarily in the parotid gland.

What sonographic features suggest malignant salivary gland tumors?

Inhomogeneous lesions with irregular and ill-defined borders.

Which salivary gland has the highest rate of malignancy according to notes?

Submandibular gland (40–60% malignant).

What percentage of sublingual gland tumors are malignant according to the notes?

Approximately 90% malignant.

What is the histologic origin of most salivary gland tumors?

Epithelial origin.