A cyst is a sac-like structure filled with fluid, which forms within various organs, surrounded by a thin layer known as the “cyst wall.” Cysts can occur in almost any organ, but are most commonly found in the liver, kidneys, ovaries, and breasts.
Some cysts are congenital, meaning they are present from birth, or they may develop due to certain hereditary conditions (such as polycystic kidney disease or Von Hippel Lindau disease). Others form due to past surgeries or infections (like lymphocele or hydatid cysts). However, most cysts develop without a specific cause and tend to grow with age. Some cysts may not produce any symptoms, while others can cause issues like pain, swelling, nausea, or high blood pressure by pressing on surrounding tissues.
With the widespread use of imaging techniques such as ultrasound, CT scans, and MRI, cysts are now detected more frequently than in the past. Small cysts that do not cause any symptoms typically do not require treatment, and periodic monitoring is sufficient. However, large cysts, those that grow rapidly, or those causing symptoms usually require treatment. Surgery, once the only treatment option, is now rarely performed; sclerotherapy, a procedure guided by imaging, has become the standard treatment for cysts today.
Can cysts become cancerous?
Cysts in the body are classified as “simple cysts” and “complex cysts” based on imaging findings. A simple cyst has a thin, smooth wall and contains only fluid. A complex cyst may have a thick, irregular wall and contain solid components in addition to fluid. Simple cysts are not associated with cancer, so they do not require biopsy and are either monitored or treated with sclerotherapy. Complex cysts, however, may result from abscesses, bleeding, or infections, and a small portion may be cancerous. In such cases, the cyst’s fluid should be aspirated and examined, and in some cases, a biopsy may be taken from the solid part of the cyst for pathology. Treatment decisions—whether monitoring, sclerotherapy, or rarely surgery—are based on these findings.
Liver Cysts
The most common types of liver cysts are simple cysts and hydatid cysts. Simple cysts have a thin, smooth wall and contain only fluid, while hydatid cysts, also known as “dog cysts,” often result from consuming contaminated food. On ultrasound, CT, and MRI, hydatid cysts can often be identified by their characteristic internal membranes or clusters of tiny cysts, resembling grape clusters. Special blood tests can help differentiate hydatid cysts from simple ones when needed.
For simple liver cysts, the most common treatment today is sclerotherapy. Using ultrasound guidance, a needle is inserted into the cyst, and a dye is injected to check if the cyst communicates with the bile ducts. If there is no connection, the cyst fluid is aspirated, and alcohol is injected. In most cases, a single treatment significantly reduces or eliminates the cyst, though sometimes a second session or catheter placement may be required.
For hydatid cysts, treatment also involves a needle but differs somewhat from simple cysts. Detailed information about hydatid cyst treatment is available under the “Hydatid Cyst” section.
Kidney Cysts
Simple kidney cysts are very common, especially among individuals over 50, with nearly half having at least one simple kidney cyst. Most are small, asymptomatic, and do not require treatment. However, cysts larger than 5 cm, or those causing pain, bleeding in the urine, infection, or hypertension, typically require treatment. The most commonly used treatment for kidney cysts is alcohol sclerotherapy. Studies show that over 90% of kidney cysts either shrink significantly or disappear after a single sclerotherapy session, along with a marked reduction in symptoms.
Sometimes, kidney cysts may develop due to a hereditary condition known as polycystic kidney disease, which involves numerous cysts and can lead to kidney failure later in life. In such cases, sclerotherapy can help alleviate pain.
Hydatid cysts are rarely found in the kidneys and can be treated with sclerotherapy. Occasionally, kidney cancers may appear as cysts on CT or MRI, and a needle biopsy is used for diagnosis in these cases.
Ovarian (Over) Cysts
Ovarian cysts are quite common, with most being simple cysts, followed by endometriotic cysts (chocolate cysts). Simple cysts generally do not require treatment as they often regress on their own, although some may respond to medication or continue growing. Chocolate cysts, containing blood, can cause severe pain during menstruation.
For growing simple cysts and painful chocolate cysts, surgical removal is often recommended. However, since surgery involves anesthesia and incision, as well as risks like infection and adhesions, many patients prefer non-surgical treatments. The most widely used alternative worldwide is ultrasound-guided sclerotherapy. In this procedure, an ultrasound-guided needle aspirates the cyst fluid, and the cyst wall is treated with an alcohol-based solution. Pathology analysis is performed on the aspirated fluid. Research indicates that over 82-85% of ovarian cysts are reduced or disappear permanently after ultrasound-guided sclerotherapy, with significant pain reduction for endometriosis patients.
Sclerotherapy is recommended for ovarian cysts that display benign characteristics, especially when CA-125 levels are normal. Studies have shown that ovarian cancer risk is negligible in such cases, especially for women under 50. In cases of cancer suspicion, however, traditional surgery is preferred.
Breast Cysts
Breast cysts are common, with most being simple cysts and few having other causes. Most breast cysts are small, asymptomatic, and do not require treatment. However, large cysts can cause discomfort or protrude visibly, requiring treatment. Previously, cyst fluid was aspirated by palpation without imaging, which carries risks such as misidentifying the cyst location or incomplete treatment. Nowadays, ultrasound guidance is used to aspirate the cyst fluid accurately, followed by alcohol injection to destroy the cyst lining, a method with a success rate of over 95% in six months. It is essential that experienced professionals perform this procedure using ultrasound to avoid complications.