Parathyroid adenoma (primary hyperparathyroidism) - information and specialists

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Leading Medicine Guide Editors

A parathyroid adenoma is a benign growth of the parathyroid gland. This leads to an overactive parathyroid gland (hyperparathyroidism) and an increase in the calcium level in the blood (hypercalcemia).

Find out more about parathyroid adenoma here and find selected specialists for the treatment of this parathyroid disease.

ICD codes for this diseases: D35.1

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Article overview

What is a parathyroid adenoma?

A parathyroid adenoma is a benign growth of the parathyroid gland. Parathyroid glands are endocrine glands that occur on both sides of the thyroid gland.

Like the thyroid gland, they produce hormones. The hormone product of the parathyroid glands is parathyroid hormone.

In the case of a parathyroid adenoma, there is an excessive release of parathyroid hormone, resulting inhyperparathyroidism.

The parathyroid hormone increases the concentration of calcium in the blood and promotes the release of calcium from the bones, kidneys and intestines. As a result, patients with parathyroid adenoma experience an increase in blood calcium levels (hypercalcemia).

A healthy parathyroid gland regulates the calcium balance via the parathyroid hormone and a feedback mechanism. Once a physiological calcium level is reached, parathyroid hormone production decreases.

This feedback mechanism does not work in the case of an adenoma. The hormone is produced in an uncontrolled manner and leads to

  • An increased release of calcium from the bones
  • Calcium absorption in the intestine

Symptoms of a parathyroid adenoma

If there is a high amount of calcium in the blood in the long term, pathological changes occur.

The following are frequently affected

  • Kidneys
  • stomach
  • intestines
  • Musculoskeletal system

Hyperparathyroidism causes symptoms that are often very unspecific. Patients therefore usually experience a long course of the disease before a diagnosis is made.

The following symptoms can occur with a parathyroid adenoma:

Development of parathyroid adenoma - causes & risk factors

Parathyroid adenoma is a tumor in the tissue of the parathyroid gland. It can occur on one or both sides.

Tumors are caused by the degeneration of cells due to persistent inflammation or mutations in the genetic material. Uncontrolled cell division leads to cell proliferation and thus to tissue overgrowth. The degenerated adenoma cells continuously produce parathyroid hormone.

In most cases,parathyroid adenomas occur sporadically and usually affect one parathyroid gland (solitary parathyroid adenoma).

More rarely, all parathyroid glands can be affected(multi-gland hyperplasia). In most cases, the cause of the degeneration and the development of the adenoma remains unknown.

Risk factors include

  • Trauma
  • injuries
  • Exposure to radiation in the neck area
  • In rare cases, there is a genetic predisposition to parathyroid adenoma, such as
  • MEN (multiple endocrine neoplasia)
  • FIHP (familial isolated hyperparathyroidism)

Women are more frequently affected by parathyroid adenoma than men. If it occurs, it usually develops between the ages of 50 and 60.

Examination procedure and diagnostic methods

If the doctor detects an elevated calcium level during a routine blood test, the parathyroid adenoma is a possible cause.

If patients report symptoms of hyperparathyroidism, a parathyroid hormone-producing adenoma is present in around 80 percent of cases.

Parathyroid hyperplasia or parathyroid carcinoma areless likely .

These diseases are initially differential diagnoses. Further examinations will show whether the diagnosis is correct or not.

To detect a parathyroid adenoma , the doctor uses the results of the blood values. In addition to the laboratory values(elevated calcium and parathyroid hormone), an imaging procedure (sonography) is usually used.

In most cases, the enlarged parathyroid glands can be localized and measured using ultrasound .

Ultraschall Nebenschilddrüsenadenom
Fig. 1: Sonography showing a parathyroid adenoma (courtesy of Dr. Diekmeyer, Clinical Director of Nuclear Medicine, Bundeswehr Central Hospital Koblenz)

An additional parathyroid scintigraphy confirms 90 percent of the localization findings suspected by sonography (Fig. 2).Nebenschilddrüsenszintigraphie
Fig. 2: Classic parathyroid scintigraphy (late image with SPECT/CT) showing a parathyroid adenoma (with kind permission from OFA Dr. Diekmeyer, Clinical Director of Nuclear Medicine, Bundeswehr Central Hospital Koblenz)

If sonography and scintigraphy do not determine a reliable localization of the adenoma, the following imaging procedures are used:

  • 4D computed tomography (Fig. 3)
  • 4D magnetic resonance imaging
  • Choline PET CT (Fig. 4)

Nebenschilddrüsenadenom 4D-CT
Nebenschilddrüsenadenom 4D-CT
Nebenschilddrüsenadenom 4D-CT
Fig. 3 a-c: Depiction of a parathyroid adenoma in 4D CT in the native, arterial and venous phase, after neither sonography nor parathyroid scintigraphy could ensure localization of the adenoma (with the kind permission of OTA PD Dr. Waldeck, Clinical Director of Radiology and Neuroradiology, Bundeswehr Central Hospital Koblenz)

Nebenschilddrüsenadenom Cholin-PET-CT
Fig. 4: Depiction of a parathyroid adenoma in choline PET-CT, after neither sonography nor parathyroid scintigraphy and 4D-CT could ensure a localization of the adenoma (with kind permission of OFA Dr. Diekmeyer, Clinical Director of Nuclear Medicine, Bundeswehr Central Hospital Koblenz)

Hyperparathyroidism is a consequence of parathyroid adenoma. It can affect and damage many organs. The doctor therefore orders additional examinations of all organs involved.

These range from urinalysis, ultrasound examinations of the kidneys and abdominal organs to x-rays of the bones (bone density) and ECG.

Treatment options and specialists

In the case of a parathyroid adenoma, the GP will consult a specialist. In addition to an endocrinologist, a nuclear medicine specialist may also be considered. Depending on the symptoms and organ involvement, treatment by other specialists such as gastroenterologists, nephrologists or neurologists may be necessary.

Parathyroid surgery is the treatment option of choice to combat the effects of primary hyperparathyroidism. Observation of the parathyroid adenoma through regular medical check-ups is only possible in asymptomatic cases.

For surgical removal of the adenoma, patients should seek treatment at a clinic specializing in endocrine surgery, including certified centers for thyroid and parathyroid surgery(http://www.dgav.de/zertifizierung/zertifizierte-zentren.html).

In the case of a parathyroid adenoma, the surgeon removes the affected parathyroid gland (Fig. 5). In over 85 percent of cases, the tumor is unilateral and is located in one of the caudal (lower) glandular corpuscles.

In order to maintain the function of the parathyroid gland and prevent a lack of parathyroid hormone, the healthy parathyroid glands remain attached to the thyroid tissue. A lack of parathyroid hormone is also called parathyroid hypofunction.

Nebenschilddrüsenadenom nach Resektion
Fig. 5: Typical macroscopic image of a parathyroid adenoma after surgical removal (courtesy of OTA Prof. Dr. Schwab, Clinical Director of General, Visceral and Thoracic Surgery, Bundeswehr Central Hospital Koblenz)

The operation to remove the adenoma is performed under general anesthesia. The procedure can be performed as a minimally invasive procedure if an isolated adenoma is present.

Minimally invasive methods have the advantage that they only cause minimal damage to the tissue. In addition, the healing phase and recovery time after the operation are shorter. In the case of multiple adenomas and the involvement of other glandular bodies, the surgeon chooses a conservative surgical method.

The vocal cord nerves and thyroid vessels run through the surgical area and are spared during the removal of the tissue. Doctors carry out intraoperative neuromonitoring of the nerve to monitor the vocal cord nerve.

A pathological examination of the removed parathyroid gland and measurement of the parathyroid hormone level are carried out during the operation. This is how doctors ensure the success of the therapy.

Course of the disease and prognosis for a parathyroid adenoma

Primary hyperparathyroidism can be successfully treated by removing the overactive parathyroid tissue.

In the case of a solitary adenoma without serious organ damage, there is a chance of recovery for the patient . The parathyroid hormone level and the functionality of the affected organs return to normal. After the operation, patients are given vitamin D and calcium supplements to compensate for a parathyroid hormone deficiency. Also to stabilize the calcium balance.

The prognosis isless favorable if there is organ damage to the kidneys or bones. These are generally not reversible.

After removal of the four epithelial bodies, it can be difficult to adjust the calcium levels. This worsens the overall prognosis.

Long-term substitution therapy with calcium and vitamin D is not sufficient in individual cases. Therefore, hormone replacement therapy with a recombinant parathyroid hormone is the only option in these cases. Hormone replacement therapy has been used since 2017, but it requires extensive endocrinological monitoring.

In the case of parathyroid adenoma, treatment consists of removing the abnormal tissue. As the healthy part of the parathyroid glands takes over the function, many patients are symptom-free after the operation and a short recovery period.

However,regular follow-up checks are important to keep an eye on calcium levels.

References

www.aerzteblatt.de/archiv/34757/Primaerer-Hyperparathyreoidismus-Heute-ein-meist-asymtomatisches-Krankheitsbild www.deutsches-schilddruesenzentrum.de/wissenswertes/nebenschilddruese/ www.laekh.de/heftarchiv/ausgabe/artikel/2022/januar-2022/chirurgie-der-nebenschilddruesen-aktuelle-diagnostik-und-therapie www.ema.europa.eu/en/medicines/human/EPAR/naptar
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