5.DEC.2017 3 MIN READ | 3 MIN READ

It can be worrying to find out you have a kidney cyst, especially as the condition does not always cause symptoms and may come as a surprise.

In many cases, your cyst will not need treatment at all. But if it does, Dr Tan Yau Min, a urologist at Mount Elizabeth Hospital, clarifies what you need to know.

What are kidney cysts?

Kidney cysts are fluid-filled, sac-like collections that appear either on the surface of your kidney, or inside the kidney itself.

Most kidney cysts don’t cause any symptoms. Often, they are simply discovered during a routine health check or ultrasound checking for other conditions.

If your cyst isn’t causing you trouble, you likely won’t need treatment. Your doctor will just keep an eye on you to make sure it doesn’t cause problems further down the line.

However, you may need further treatment if the cyst:

  • Changes in size
  • Causes aches and pains
  • Bleeds
  • Becomes infected, causing a fever or chills
  • Impairs usual kidney function

Is there a chance my cyst could be cancerous?

The risk of a kidney cyst becoming cancerous is ranked using the Bosniak classification score, so-named after renowned radiologist Morton Bosniak from New York University.

The rankings are as follows:

  • Bosniak 1: Less than 1% risk of cancer. No follow-up required
  • Bosniak 2: Less than 5% risk of cancer. No follow-up required
  • Bosniak 2F: 5% risk of cancer. Follow-up required to assess condition
  • Bosniak 3: 50% risk of cancer. Surgery required to test or remove the cyst
  • Bosniak 4: 80% – 95% risk of cancer. Surgery required to remove the cyst

Based on an ultrasound, your doctor will inform you of your cyst’s classification and explain the next steps.

What happens if I need to have a cyst removed?

It is nearly always best to have a Bosniak 3 or 4 cyst removed surgically. Most doctors recommend a partial surgery for cysts smaller than 4cm, which removes the cyst but preserves as much of the remaining kidney as possible. This can help to stabilise kidney function, which lowers your risk of developing other related conditions in the future, such as heart disease.

If your cysts are not cancerous but are very painful, your doctor may still perform minimally invasive surgery to remove the cyst. Alternatively, they may suggest draining the cyst and then replacing the fluid inside with an alcoholic solution, a simple procedure which hardens the tissue and helps to prevent the cyst from growing back.

If you have a severe infection or lose kidney function, but your other kidney is still functioning well, your doctor may recommend removing the poorly functioning kidney entirely. This can help to prevent the risk of recurring infections or future cancerous changes.

How frequently should I see the doctor for a follow-up?

Most doctors recommend leaving 6 or 12 months between ultrasound tests for Bosniak 2 or 2F cysts. Your doctor will inform you of the recommended timeframe for you.

What happens if I have multiple cysts?

Multiple cysts may indicate a genetic condition, such as polycystic kidney disease, which destroys healthy kidney tissue. To diagnose this, your doctor will review your family history and conduct ultrasound or computer-enhanced X-ray scans to look for cysts.

If you are diagnosed with a genetic kidney condition, there is a possibility of renal failure. This loss of function can result in dialysis or the need for a kidney transplant. However, your doctor will work closely with you to manage symptoms and avoid these complications. They may recommend you take pain or blood pressure medication as well as undertake cyst drainage procedures to keep the growth of cysts under control.

You may also wish to speak to a dietitian, who can help you create a nutrition plan that eases the pressure on your kidneys and lowers your blood pressure.

If you are concerned about your symptoms or struggling with your diagnosis, consult your doctor for more advice and to gain access to support services.


Article contributed by Dr Tan Yau Min, urologist at Mount Elizabeth Hospital

Tan Yau Min Gerald
Mount Elizabeth Hospital

Dr Gerald Tan is a urology specialist at Mount Elizabeth Novena Hospital who is well known for his expertise in minimally invasive and robotic surgery and for prostate, kidney and bladder cancers.