OVERVIEW

What is a parathyroid cyst?

The parathyroid glands are small, oval-shaped glands. About 85% of people have two pairs (four in total), with the upper pair usually located above the thyroid and the lower pair adjacent to the lower lobes of the thyroid.

A parathyroid cyst is a cyst that develops in the parathyroid glands and is uncommon. Based on clinical presentation, parathyroid cysts can be classified into functional and non-functional types.

• Non-functional parathyroid cysts account for 85% of cases and primarily present as neck masses. Depending on their location or size, these masses may compress adjacent tissues, causing discomfort such as a foreign body sensation during swallowing, difficulty breathing, or voice changes.
• Functional parathyroid cysts account for 15% of cases. In addition to neck masses, they may also cause symptoms related to hyperparathyroidism, such as bone and joint pain or kidney stones.

Surgical treatment is the primary approach for this condition, with good therapeutic outcomes.

Are parathyroid cysts common?

No, they are uncommon, accounting for 1%–5% of neck masses.

SYMPTOMS

What are the common manifestations of parathyroid cysts?

• Mass effect of the cyst: Mainly manifests as neck thickening or the discovery of a neck mass. If the cyst compresses adjacent tissues, discomfort may occur, such as a foreign body sensation during swallowing, difficulty breathing, or changes in voice.
• Functional effect of the cyst: Primarily presents as symptoms related to hyperparathyroidism, such as:
  • Bone manifestations: Pain in both lower limbs, localized tenderness, fatigue, difficulty walking, etc., which may gradually progress to systemic bone and joint pain, even leading to being bedridden, loss of self-care ability, height reduction, and fractures.
    Kidney manifestations: Polyuria, nocturia, polydipsia, etc., with a tendency to form bilateral and multiple urinary tract stones or renal parenchymal calcification, presenting as hematuria, renal colic, or even turbid urine resembling rice water.
  • Digestive system manifestations: May include poor appetite, nausea, bloating, constipation, ulcers, or pancreatitis.
  • Skin manifestations: May include itching.
  • Neuropsychiatric manifestations: May include emotional instability, fatigue, irritability, memory decline, weakness, and slow reactions.

Where do parathyroid cysts commonly occur?

Parathyroid cysts occur in the parathyroid glands and can affect any of the four glands, but they are more commonly found in the left inferior parathyroid gland.

CAUSES

What are the common causes of parathyroid cysts?

The exact cause of parathyroid cysts remains unclear, but possible factors include:

• Cystic degeneration or intratumoral hemorrhage of parathyroid adenomas;
• Residual tissue from the third or fourth pharyngeal pouches during embryonic development;
• Fusion of multiple microcysts or fluid retention forming a large cyst within the parathyroid gland.

Who is more likely to develop parathyroid cysts?

The average age of onset for parathyroid cysts is 49 years, with middle-aged women being more commonly affected. The male-to-female ratio is approximately 1:1.85.

Are parathyroid cysts contagious?

Parathyroid cysts are not contagious.

Are parathyroid cysts hereditary?

Currently, parathyroid cysts are not considered hereditary.

DIAGNOSIS

How to Diagnose a Parathyroid Cyst?

When diagnosing a parathyroid cyst, doctors primarily consider the following:

• The patient exhibits related symptoms;
• Blood tests reveal signs of hyperparathyroidism, such as elevated calcium levels and increased parathyroid hormone levels;
• Imaging tests, including ultrasound, CT, or parathyroid scintigraphy, detect the presence of a parathyroid cyst;
• If necessary, fine-needle aspiration of the parathyroid cyst may be performed to aid in further diagnosis.

What Tests Are Needed if a Parathyroid Cyst Is Suspected?

Generally, qualitative and localization tests are required, and fine-needle aspiration under ultrasound guidance may be performed if necessary.

• Qualitative tests: Used to determine whether the parathyroid cyst is functional, such as elevated blood calcium, decreased blood phosphorus, increased alkaline phosphatase levels, and elevated parathyroid hormone levels.
• Localization tests: Used to confirm the presence of a parathyroid cyst. Ultrasound is the first choice, while ⁹⁹mTc-MIBI parathyroid scintigraphy, CT, and MRI can also assist in diagnosis and preoperative localization.
• Fine-needle aspiration under ultrasound guidance: This serves as both a diagnostic method—measuring parathyroid hormone levels in the cyst fluid can confirm the diagnosis—and a treatment approach. However, simple aspiration often leads to recurrence, and some argue that post-aspiration surgery may increase the risk of incomplete removal and recurrence. Therefore, fine-needle aspiration should be carefully evaluated and selected.

TREATMENT

Which department should I visit for parathyroid cysts?

For parathyroid cysts, you should visit the endocrinology department and thyroid surgery department.

Can parathyroid cysts heal on their own?

Parathyroid cysts do not heal on their own and usually require surgical treatment.

How are parathyroid cysts treated?

The primary treatment for parathyroid cysts is currently surgical intervention.

• For functional parathyroid cysts, simple cyst enucleation is performed directly.
• For definitively diagnosed non-functional parathyroid cysts with a diameter less than 4 cm and no clinical compressive symptoms, surgery may be temporarily deferred, and regular follow-up monitoring is sufficient.
• For definitively diagnosed non-functional parathyroid cysts with clinical compressive symptoms or a diameter greater than 4 cm, and in patients with generally good health, surgical treatment is recommended. For patients in poor health who cannot tolerate surgery, simple aspiration, injection of absolute ethanol, or radiofrequency/microwave ablation may be considered.

Is hospitalization required for parathyroid cysts?

Unless surgery is deferred and regular follow-up is planned, hospitalization is required for the treatment of parathyroid cysts.

What are the common risks of surgical treatment for parathyroid cysts?

A common risk after surgical treatment for parathyroid cysts is hypoparathyroidism, which is mostly temporary. Permanent hypoparathyroidism is relatively rare.

Can parathyroid cysts be completely cured?

Most parathyroid cysts can be completely cured without leaving sequelae, and the recurrence rate is low.

DIET & LIFESTYLE

What are the precautions after surgical treatment of parathyroid cysts? How to care for it?

Postoperative precautions for patients with parathyroid cysts:

• Monitor for abnormal symptoms such as hoarseness, difficulty swallowing, or choking. If these occur, communicate with the doctor promptly;
• Watch for numbness around the lips, hands, or feet, which may indicate low blood calcium levels. Inform the doctor immediately for timely treatment adjustment;
• Postoperative diet should include high-calcium, low-phosphorus foods such as fruits, vegetables, milk, soy products, dried shrimp, and sesame seeds. Vitamin D supplementation can aid calcium absorption;
• Schedule regular follow-ups, including blood calcium tests, parathyroid hormone checks, and neck ultrasound or CT scans.

PREVENTION

Can parathyroid cysts be prevented? How to prevent them?

Since the cause and pathogenesis of parathyroid cysts are not yet clear, there are no definitive and effective measures for prevention.