Parathyroid Gland Pathology Flashcards
What do chief cells look like?
- Central round, uniform nuclei
- Light pink or white cytoplasm
- Secretory granules
What do oxyphil cells look like?
- Smaller, darker nuclei
- Eosinophilic granular material
- Less endocrinologically active
What is the principle function of the parathyroid gland?
- Calcium homeostasis
What does the parathyroid hormone do?
- Directly releases calcium from bone
- Exerts effects on the kideny
What effects does parathyroid hormone have on the kidneys?
- Calcium resorption –> blocks phosphate resorption
- Conversion of 25(OH)D to 1,25(OH)2D in the kidney –> further mobilizes calcium from bone and intestine
How does the parathyroid gland know what to do?
- Calcium-sensing receptor (CaSR) regulates the amount of PTH secreted from the parathyroid glands
What does low serum calcium result in?
- Increased PTH secretion
What does high serum calcium result in?
- PTH repression
What is the most common cause of primary hyperparathyroidism?
- Adenoma
What are the symptoms of primary hyperparathyroidism?
- Painful bones
- Renal stones
- Abdominal groans
- Psychic moans
- “Bones, stones, groans, and moans”
What causes the painful bones in primary hyperparathyroidism?
- Osteoporosis
- Osteitis fibrosis cystica
What causes the abdominal groans in primary hyperparathyroidism?
- Constipation
- Gallstones
What causes the psychic moans in primary hyperparathyroidism?
- Depression
- Lethargy
- Seizures
What is osteitis fibrosis cystica?
- Starts as a brown tumor
- Osteoclast-driven bone destruction
- Small fractures
- Hemorrhage and reactive tissue
What is the main way that primary hyperparathyroidism is diagnosed?
- In an asymptomatic patient, through routine bloodwork
What is a parathyroid adenoma?
- Benign neoplasm of parathyroid chief or oxyphil cells
- Typically solitary
- Can be surrounded by a rim of normal parathyroid tissue
What happens to the other parathyroid glands in a parathyroid adenoma?
- The other glands atrophy due to the abnormal levels of PTH and calcium
What is parathyroid hyperplasia?
- Almost always present in multiple glands
- Secondary hyperplasia is MUCH more common
- No normal rim of parathyroid tissue
What may be responsible for parathyroid hyperplasia?
- MEN syndromes (rare sporadic forms)
How do you tell the difference between adenoma and hyperplasia?
- One gland affected: adenoma
- Multiple glands affected: hyperplasia
What is the treatment for an adenoma?
- Surgery excision
- Within minutes of excision, hormone levels with fall
What is the telltale sign of parathyroid carcinoma?
- Metastasis
- Highly suggestive sings: invasive of adjacent tissue and vascular invasion
What does the hypercalcemia cause in hyperparathyroidism?
- Most likely to be asymptomatic or have subtle symptoms
- Most commonly due to parathyroid adenoma
What does hypercalcemia cause in non-parathyroid sources?
- More likely to be overt/symptomatic
- Mental status changes, N/V, EKG changes – shortened QT interval
