A kidney cyst is a fluid-filled sac that develops on one or both of the kidneys. These cysts are round, thin walled and can range in size from microscopic to around 5cm in diameter. They may be associated with a serious condition, but in most cases they are harmless and referred to as simple kidney cysts.
These simple cysts do not usually lead to any symptoms or kidney damage, although they can cause problems if they become large enough or start to press on other organs.
If a cyst is found to be simple, no further monitoring or evaluation is usually required. A complex kidney cyst is a cyst that has a more irregular shape or thicker walls than a simple cyst. Imaging techniques may be used to periodically assess a complex cyst. If it has become large enough to cause pain, discomfort, or high blood pressure, it may need to be surgically removed.
Some complex cysts may also be removed due to an increased risk of kidney cancer or because the patient is experiencing a decline in kidney function.
Some of the approaches used to remove a cyst are described below.
Retrograde Intrarenal Surgery
This procedure is the treatment of choice for cases where a cyst can be accessed from the part of the kidney basin involved in draining. A small telescope is passed into the ureter through to the kidney, where a laser is used to make a cut in the cyst and open it so that it can be drained. A stent is placed in the ureter, where it remains for around two weeks to ensure complete healing.
Percutaneous Kidney Surgery
This type of surgery is employed in case of larger cysts that have developed in the posterior of the kidney. This minimally invasive technique enables the surgeon to perform endoscopic surgery on the kidney using a small opening called a tract. A tract is created by making a small cut in the skin and tissue, straight into the kidney.
To bridge the distance between the kidney and the skin, a sleeve is placed into the organ. Endoscopic instruments are then guided through the sleeve and into the kidney so that the cyst can be opened and a large portion of the wall removed under X-ray guidance. The patient usually needs to stay overnight in hospital for this procedure.
Laparoscopy and Removal of the Cyst
This is usually performed when a patient has multiple cysts or a very large cyst. Laparoscopy and cyst removal is the most suitable treatment for a genetic condition called polycystic kidney disease (PKD).
A person with PKD has a large number of cysts that cause scarring of the healthy kidney tissue, which eventually can lead to impaired kidney function. Here, three small incisions are made in the abdomen, small instruments are passed through to the kidney and the cysts removed. When a large number of cysts need to be removed, this procedure may require an overnight stay at the hospital.
Reviewed by Susha Cheriyedath, MSc