Pathology - Parathyroid

Question 1

What three types of cells are normally seen in a parathyroid histologically?

Answer 1

Chief cells, oxyphil cells, adipose cells

Question 2

Describe the extent of gland involvement in parathyroid hyperplasia vs. parathyroid adenoma. What differences between these two can be seen histologically?

Answer 2

Hyperplasia involves all four glands, while adenomas usually involve only one gland.

Histologically, hyperplasia would show increased cellularity of both oxyphil and chief cells. In an adenoma, only one cell type proliferates so you’d see a monotony histologically (see photo).

Question 3

Explain how chronic kidney disease can cause secondary hyperparathyroidism.

Answer 3

Kidneys can’t excrete phosphate, and they also don’t make vitamin D3 –> phosphate binds calcium in the blood, gut doesn’t absorb calcium –> calcium levels stay low –> PTH keeps getting made

Question 4

What is the pathogenesis of tertiary hyperparathyroidism?

Answer 4

It occurs after a long period of secondary hyperparathyroidism - parathyroids are stimulated to make PTH for so long, and they start autonomously secreting PTH even after calcium levels are restored to normal