What is the Difference Between Parathyroid Adenoma and Hyperplasia?

Parathyroid adenoma and hyperplasia are both conditions that can lead to hyperparathyroidism, a condition where the parathyroid glands produce too much parathyroid hormone (PTH). However, they differ in the way they develop and are treated surgically.

Parathyroid Adenoma:

• A benign tumor that develops inside a parathyroid gland.
• Usually only one gland is affected, while the other parathyroid glands may become atrophic.
• Growth patterns can range from solid to pseudo-glandular, follicular, and acinar, with occasional cystic degeneration.
• Nuclear pleomorphism is usually focal and seen in clusters.
• Mitotic figures are inconspicuous (<1/10 hpf), and atypical mitotic figures should not be seen.
• Immunohistochemical studies are generally not necessary for diagnosis.

Parathyroid Hyperplasia:

• A condition where all parathyroid cells in all parathyroid glands are abnormal, causing all the glands to grow and produce PTH.
• All four parathyroid glands are affected, although they are not necessarily enlarged.
• Clinically involves more than one gland, while adenomas are usually singular.
• Occasional mitoses and larger hyperchromatic nuclei may be observed.
• Expression of p27 and Ki67 may be helpful in the diagnosis of histologically overlapping lesions.

Both conditions can lead to the same symptoms and consequences, but the treatment is different. It can be challenging to distinguish between the two conditions based on symptoms or lab tests alone. In the past, sampling of the other glands was required to rule out parathyroid hyperplasia, but with the accuracy of radiographic imaging and intraoperative parathyroid hormone monitoring, the surgeon does not necessarily need to sample tissue from the other glands.

Comparative Table: Parathyroid Adenoma vs Hyperplasia

Parathyroid adenoma and parathyroid hyperplasia are two different medical conditions that affect the parathyroid glands, which are located behind the thyroid glands at the bottom of the neck. They both can cause hyperparathyroidism, but they have distinct differences:

It is essential to differentiate between these two conditions for proper diagnosis and treatment. While the end result of both conditions is the same (hyperparathyroidism symptoms and consequences), their development and treatment are distinct.