Your diagnosis

Enlarged and hypercellular parathyroid gland

This article will help you read and understand your pathology report for enlarged and hypercellular parathyroid gland.

by Archan Kakadekar MD and Jason K Wasserman MD PhD FRCPC, reviewed by our Patient Partners on December 8, 2020

enlarged hypercellular parathyroid gland

Quick facts:

  • Enlarged and hypercellular parathyroid gland is a term pathologists use to describe a non-cancerous type of growth involving one or more of the parathyroid glands.
  • The parathyroid glands are located in the front of the neck close to the thyroid gland.
  • The parathyroid glands produce parathyroid hormone which helps control the amount of calcium in your blood.
  • Enlarged and hypercellular parathyroid glands often produce extra parathyroid hormone (hyperparathyroidism) which can lead to increased calcium levels in the blood (hypercalcemia).

The function and anatomy of the parathyroid glands

The parathyroid glands are part of the endocrine system which means they make hormones that travel around the body through the blood stream. Most people have four small parathyroid glands that are normally found in the front of the neck close to the much larger thyroid gland.

The parathyroid glands are made up of a combination of specialized cells called chief cells, oxyphil cells, and clear cells. These cells make parathyroid hormone (PTH) which is then released into the blood stream. Parathyroid hormone is important because it helps control the amount of calcium in your blood. Calcium is needed to maintain strong bones and to help your nervous system, muscles, and digestive system function normally.

What does enlarged and hypercellular parathyroid gland mean?

Enlarged and hypercellular parathyroid gland is a term pathologists use to describe a benign (non-cancerous) growth made up of cells normally found in the parathyroid gland. The growth can involve one or more of the parathyroid glands. Unlike the normal parathyroid glands, an enlarged and hypercellular parathyroid gland may be large enough to be felt or seen in the front of the neck.

enlarged hypercellular parathyroid gland cells

Hyperparathyroidism

A hypercellular and enlarged parathyroid gland often makes extra parathyroid hormone which is then released into the blood. Doctors call this hyperparathyroidism. This leads to increased levels of calcium in the blood.  Doctors call this hypercalcemia.

Symptoms of hypercalcemia include involuntary shaking (tremor), nausea, vomiting, abdominal pain, and confusion. Patients with prolonged hypercalcemia are also more likely to suffer from broken bones and kidney stones.

What causes a parathyroid gland to become enlarged and hypercellular?

The cause of an enlarged and hypercellular parathyroid gland depends on the number of glands involved and the results of other laboratory tests performed. If only a single gland is involved and your parathyroid hormone levels return to normal after the gland is removed, the growth may represent a parathyroid adenoma.

A parathyroid adenoma is a benign (non-cancerous) type of tumour and the most common cause of hyperparathyroidism. Parathyroid adenomas are often sporadic which means doctors do not know what causes them. However, some genetic syndromes such as multiple endocrine neoplasia (MEN) and familial isolated hyperparathyroidism (FIHP), greatly increase a person’s risk for developing these tumours.

If multiple glands are involved, the condition is described as parathyroid hyperplasia. Approximately 20% of the people who develop parathyroid hyperplasia have the genetic syndrome multiple endocrine neoplasia (MEN). People with chronic kidney disease are also more likely to develop parathyroid hyperplasia. In this situation, the parathyroid glands may return to normal after treatment improves kidney function. A single hypercellular and enlarged parathyroid gland remains after treatment is described as tertiary hyperparathyroidism.

How do pathologists make this diagnosis?

Increased levels of parathyroid hormone or calcium in your blood are often the first signs of an enlarged and hypercellular parathyroid gland. Your doctor may also suspect the diagnosis if you have a lump in the front of your neck or symptoms related to increased blood calcium (see above).

If the growth is removed it will be sent to a pathologist who examines it under the microscope. The diagnosis can usually be made by examining the a tissue sample stained with a combination of dyes called hematoxylin and eosin. However, some pathologists may perform an additional test called immunohistochemistry to confirm the diagnosis.

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