Doctors discovered a large, unusual cyst in a 55-year-old man’s neck that turned out to be a parathyroid cyst—a rare type of benign lump. Using a simple ultrasound-guided needle procedure, they drained about 90 milliliters of clear fluid from the cyst. Tests on the fluid showed high levels of parathyroid hormone, confirming the diagnosis. The good news: the cyst wasn’t causing any hormonal problems in the patient’s body, and five years of follow-up scans showed it never came back. This case shows that even large parathyroid cysts can often be safely treated with a minimally invasive needle procedure rather than surgery.

The Quick Take

  • What they studied: A single patient with a large fluid-filled sac in the neck that was mistaken for a thyroid problem but turned out to be a parathyroid cyst
  • Who participated: One 55-year-old man who had no symptoms but had a large cyst discovered by accident during an ultrasound scan
  • Key finding: Doctors used a simple needle procedure to drain the cyst, and tests showed it contained parathyroid hormone. The patient’s blood hormone levels stayed normal, and the cyst didn’t come back in five years of follow-up visits
  • What it means for you: If you’re found to have a parathyroid cyst, a simple needle drainage procedure may be all you need instead of surgery. However, this is based on one patient’s experience, so talk to your doctor about what’s best for your situation

The Research Details

This is a case report, which means doctors are sharing the story of one patient’s experience with a rare condition. A 55-year-old man came to the hospital with a large cyst in his neck that was discovered by chance on an ultrasound scan. The cyst was about the size of a golf ball and was pushing on his windpipe, but he didn’t have any symptoms like trouble swallowing or hoarseness.

The doctors used ultrasound imaging to guide a thin needle into the cyst and drained about 90 milliliters (roughly 3 ounces) of clear fluid. They then tested this fluid in the laboratory to figure out what kind of cyst it was. They measured parathyroid hormone (PTH) and thyroglobulin levels in the fluid to determine its origin.

After the procedure, the doctors followed up with the patient every six months for five years, taking ultrasound scans to make sure the cyst didn’t come back. They also checked his blood levels of calcium, PTH, and vitamin D to make sure his body’s hormone balance stayed normal.

Case reports are important because they describe unusual or interesting medical situations that doctors might not see very often. Parathyroid cysts are rare—they make up only 1-5% of all neck lumps—so sharing detailed information about how to diagnose and treat them helps other doctors recognize and manage similar cases. This case is particularly valuable because it shows that a simple needle drainage procedure can work well for these cysts, which is important information for patients who want to avoid surgery.

This is a single case report, which is the lowest level of scientific evidence. It describes what happened to one patient, but we can’t assume the same results will happen to everyone with a parathyroid cyst. The strength of this case is the long-term follow-up (five years) with regular imaging, which gives us confidence that the treatment worked well in this particular patient. However, more research with many patients would be needed to know how often this simple procedure works for everyone.

What the Results Show

The doctors successfully drained 90 milliliters of clear, colorless fluid from the cyst using a needle guided by ultrasound. Laboratory analysis of this fluid showed very high levels of parathyroid hormone (PTH at 1,845.80 ng/L) but very low levels of thyroglobulin (a protein made by the thyroid). This combination of results confirmed that the cyst came from the parathyroid gland, not the thyroid gland.

Despite the high PTH levels in the cyst fluid, the patient’s blood tests showed normal levels of PTH, calcium, and vitamin D both before and after the procedure. This meant the cyst was not actually affecting his body’s hormone balance—it was what doctors call a “non-functioning” cyst.

The most impressive finding was the long-term outcome: when doctors checked the patient with ultrasound every six months for five years after the procedure, they found no evidence that the cyst came back. The area where the cyst had been remained clear with no fluid re-accumulation.

The case also provides important diagnostic information. The fact that the cyst fluid had very high PTH but very low thyroglobulin was the key to correctly identifying it as a parathyroid cyst rather than a thyroid cyst. This shows that testing the fluid from a cyst is crucial for getting the right diagnosis, especially when a cyst looks like it might be a thyroid problem on imaging alone. The patient remained completely asymptomatic throughout the entire five-year follow-up period, with no complications from the needle drainage procedure.

This case fits with what doctors already know about parathyroid cysts. Medical literature shows that these cysts are indeed rare and often get misdiagnosed as thyroid nodules because they look similar on imaging. The case confirms that fine-needle aspiration (the needle drainage procedure) is an effective diagnostic tool and can also be a treatment. Previous research has shown that some parathyroid cysts can be managed with simple aspiration rather than surgery, and this case provides another example of successful long-term outcomes with this approach.

This is a single case report, so we can only say what happened to one patient. We don’t know if the same results would occur in other patients with parathyroid cysts. The patient was asymptomatic and had a non-functioning cyst, so results might be different for patients whose cysts are causing symptoms or affecting hormone levels. Additionally, we don’t know the long-term outcomes beyond five years, though five years is a reasonably good follow-up period. Finally, this case doesn’t compare the needle drainage approach to other treatment options like surgery or sclerotherapy, so we can’t say which treatment is best overall.

The Bottom Line

Based on this single case, a simple needle drainage procedure guided by ultrasound appears to be a safe and effective treatment for parathyroid cysts that are not causing symptoms or hormone imbalances. However, this recommendation comes from one patient’s experience, so it should be considered low-confidence evidence. If you’re diagnosed with a parathyroid cyst, discuss all treatment options with your doctor, including observation, needle drainage, and surgery. Regular follow-up imaging is important to make sure the cyst doesn’t come back.

This case is most relevant to people who have been diagnosed with a parathyroid cyst, particularly those who want to avoid surgery. It’s also important for doctors and radiologists who need to recognize and diagnose parathyroid cysts. People with incidental neck cysts discovered on imaging should know that parathyroid cysts are a possibility and that simple testing of cyst fluid can help identify them. However, this case describes one specific situation, so individual results may vary.

In this patient, the cyst was successfully drained in a single procedure, and there was no recurrence over five years of follow-up. However, we don’t know if this timeline applies to all patients. Some parathyroid cysts may recur sooner or later, so regular follow-up imaging is recommended. Benefits of the procedure (relief from any compressive symptoms) would likely be immediate, but long-term success requires ongoing monitoring.

Want to Apply This Research?

  • If you have a parathyroid cyst being monitored, track your follow-up ultrasound appointments and blood test results (PTH, calcium, vitamin D levels) in your health app. Set reminders for your scheduled imaging appointments, typically every 6 months initially, and log any new symptoms like neck swelling, difficulty swallowing, or voice changes.
  • Work with your healthcare provider to establish a monitoring schedule and stick to it. Use your app to set calendar reminders for ultrasound appointments and blood work. Document any symptoms you experience between appointments so you can discuss them with your doctor. This helps catch any changes early and ensures you’re getting appropriate follow-up care.
  • Create a long-term tracking system in your app that records: (1) dates and results of ultrasound imaging, (2) blood test results for PTH, calcium, and vitamin D, (3) any symptoms or changes you notice, and (4) appointments with your endocrinologist or surgeon. Review this information regularly with your healthcare provider to ensure your cyst remains stable and non-functional.

This case report describes the experience of one patient and should not be considered medical advice for your individual situation. Parathyroid cysts are rare, and treatment options vary depending on whether the cyst is causing symptoms, affecting hormone levels, and other individual factors. If you have been diagnosed with a parathyroid cyst or have a neck mass, consult with your healthcare provider or an endocrinologist to discuss the best treatment approach for your specific case. Do not attempt any self-treatment based on this information. This article is for educational purposes only and does not replace professional medical evaluation and care.