Splenic Cyst

What is splenic cyst?

A splenic cyst is a fluid-filled sac that forms inside the spleen. The spleen is an organ about the size of a fist that sits in the upper left part of the abdomen, behind the ribs and next to the stomach. It filters the blood, removes old or damaged blood cells, and helps the immune system fight certain infections. A cyst is a closed pocket, usually with a thin wall, that contains fluid or semi-solid material rather than normal tissue.

Splenic cysts are uncommon compared with cysts in organs such as the liver or kidneys. Most are benign, which means they are not cancer and do not spread to other parts of the body. Doctors usually group them into two broad categories:

• Parasitic cysts, which are caused by an infection, most often a tapeworm infection called echinococcosis (also known as hydatid disease). These are more common in regions where people live closely with sheep, cattle and dogs.
• Nonparasitic cysts, which are further divided into primary (true) cysts that have a lining of specialized cells on the inside, and secondary cysts (also called pseudocysts) that have no such lining and usually develop after an injury to the spleen.

A splenic cyst can affect people of any age. Primary cysts are often found in children and young adults, while secondary cysts can appear at any age after a blow to the abdomen. Many splenic cysts are discovered by chance during imaging done for another reason, because small cysts frequently cause no symptoms at all.

Splenic cyst symptoms

Splenic cyst symptoms depend largely on the size of the cyst, how quickly it grows, and whether it presses on nearby organs. Small cysts, especially those under a few centimeters, often cause no symptoms and may never be noticed without a scan. As a cyst becomes larger, it can stretch the outer covering of the spleen or push against the stomach, the left kidney, the diaphragm (the muscle that helps you breathe) or the bowel.

Common symptoms of a larger splenic cyst may include:

• A dull ache or feeling of fullness in the upper left abdomen
• Pain that spreads to the left shoulder or back
• Feeling full quickly after eating only a small amount
• Nausea, bloating or occasional vomiting
• A visible or palpable lump under the left ribs
• Shortness of breath or discomfort when taking a deep breath
• A persistent cough or hiccups if the cyst presses on the diaphragm
• Mild pain in the left flank or side

Symptoms can differ by type. A parasitic cyst may cause, in addition to the pressure symptoms above, an allergic-type reaction such as hives or itching if fluid leaks from the cyst. In rare cases a leaking parasitic cyst can trigger a severe allergic reaction, which is a medical emergency. A secondary cyst that follows an injury may be noticed weeks or months after the original trauma, sometimes with a slowly increasing sense of fullness on the left side.

Complications are uncommon but important. A cyst can become infected, causing fever, chills and worsening pain. A very large cyst can rupture, either spontaneously or after a minor knock, which may lead to sudden severe abdominal pain and internal bleeding. Because the spleen has a rich blood supply, a rupture needs urgent medical care.

Causes and risk factors

Splenic cyst causes vary according to the type of cyst. In many cases the exact reason a cyst forms is never fully explained, but doctors recognize several recognized pathways.

Congenital (present from birth) development. Primary or true cysts are thought to arise when small groups of lining cells become trapped inside the spleen while it is forming before birth. Over years these cells can produce fluid and slowly enlarge into a cyst. These are sometimes called epidermoid or epithelial cysts. They are the most common type in children and young adults and are not caused by anything the person did.

Injury to the spleen. Secondary cysts or pseudocysts often develop after a blunt injury to the abdomen, such as a fall, a sports collision or a road traffic accident. Bleeding inside the spleen forms a collection of blood that the body gradually breaks down, leaving a fluid-filled space surrounded by scar tissue. A pseudocyst can also follow a splenic infarction, which is an area of tissue that died because its blood supply was blocked, or a previous infection or abscess in the spleen.

Parasitic infection. Echinococcosis is caused by the larval stage of a small tapeworm that normally lives in dogs. People become infected by swallowing microscopic eggs, usually through contaminated food, water or contact with an infected animal. The larvae travel through the bloodstream and can settle in the liver, lungs or, less commonly, the spleen, where they form a slowly growing cyst.

Other rare causes. A small number of cystic-appearing lesions in the spleen are actually other conditions, such as a cluster of abnormal lymphatic vessels (a lymphangioma), a blood-vessel tumor (a hemangioma) with cystic areas, or an abscess. Doctors consider these when the imaging appearance is unusual.

Risk factors that may make a splenic cyst more likely include:

• A history of blunt trauma to the abdomen or left lower chest
• Living in or traveling to areas where echinococcosis is common, particularly rural sheep-farming regions
• Close contact with dogs that may carry the tapeworm, or handling livestock
• A previous splenic abscess, infarction or pancreatitis (inflammation of the pancreas, which lies next to the spleen)
• Being a child or young adult, for congenital cysts

Splenic cysts are not thought to be inherited in a simple family pattern, and they are not caused by diet, stress or lifestyle choices.

Splenic cyst diagnosis

Splenic cyst diagnosis usually starts with a conversation about symptoms and medical history, including any past abdominal injuries, travel to rural areas and contact with animals. During a physical examination, the doctor may gently press on the upper left abdomen to feel whether the spleen is enlarged or tender. However, physical examination alone cannot confirm a cyst, so imaging tests are essential.

Ultrasound. This is often the first test. It uses sound waves to create a picture of the spleen and can show whether a lesion is fluid-filled, how large it is, and whether it has a smooth wall, internal septations (thin dividing walls) or floating debris. Ultrasound is painless and does not use radiation.

CT scan (computed tomography). A CT scan uses X-rays and a computer to make detailed cross-sectional images. It helps define the exact size and position of the cyst, its relationship to nearby organs and blood vessels, and whether the wall contains calcium deposits, which can suggest a long-standing or parasitic cyst. Contrast dye is often given through a vein to improve the images.

MRI (magnetic resonance imaging). MRI uses magnetic fields rather than radiation and gives excellent detail of the fluid inside the cyst. It is sometimes used when ultrasound and CT leave questions, or in children and pregnant women to avoid radiation.

Blood tests. If a parasitic cyst is suspected, doctors may order blood tests that look for antibodies against the echinococcus parasite. A complete blood count and other routine tests help check for infection or anemia. Some doctors also measure certain tumor markers, since these can occasionally be raised in true epithelial cysts, although this is not a definitive test.

Why biopsy is usually avoided. Unlike many other organs, the spleen is rarely biopsied with a needle, because of the risk of bleeding and, in the case of a parasitic cyst, the risk of spreading infection or causing a severe allergic reaction. For this reason the diagnosis is based mainly on imaging features, history and blood tests. The final classification of a cyst as primary or secondary is often only confirmed after it has been removed and examined under a microscope.

Doctors also use imaging to distinguish a simple cyst from an abscess, a solid tumor with cystic areas, or a cyst arising from the pancreas or kidney that happens to touch the spleen. Careful review by a radiologist, a doctor who specializes in interpreting scans, is an important part of the process.

Treatment options

Splenic cyst treatment depends on the size and type of the cyst, whether it is causing symptoms, whether it is parasitic, and the age and general health of the person. There is no single correct approach, and your doctor may recommend one of several strategies.

Observation. Small, nonparasitic cysts that cause no symptoms are often monitored rather than treated. This typically involves repeat ultrasound scans at intervals to check whether the cyst is growing. Many small cysts remain stable for years, and some pseudocysts shrink or disappear on their own as the body reabsorbs the fluid. Observation avoids the risks of surgery while keeping watch for change.

Medication. For parasitic cysts, antiparasitic tablets may be prescribed, sometimes on their own for small cysts and more often before and after a procedure to reduce the risk of the infection spreading. Pain relievers may be suggested for discomfort. There is no medication that makes a nonparasitic cyst disappear.

Needle aspiration and sclerotherapy. In selected nonparasitic cysts, a radiologist may drain the fluid through a thin needle guided by imaging, sometimes injecting a substance that irritates the lining so it seals shut (sclerotherapy). This is less invasive than surgery, but the cyst frequently refills, so it is not always a lasting solution. Aspiration is generally avoided when a parasitic cyst is suspected.

Spleen-preserving surgery. Because the spleen plays a role in immunity, surgeons try to keep as much healthy spleen as possible, especially in children. Options include partial splenectomy (removing only the part of the spleen containing the cyst), cyst unroofing or marsupialization (removing the outer wall of the cyst so it can no longer fill), and cyst decapsulation (peeling the cyst wall away from the spleen). Many of these procedures can be performed laparoscopically, meaning through several small incisions with a camera, which often allows a shorter recovery than open surgery.

Total splenectomy. Removing the whole spleen may be recommended when a cyst is very large, sits deep in the center of the organ, is likely to be parasitic, has ruptured, or when spleen-preserving surgery is not technically safe. People who have their spleen removed have a lifelong increased risk of certain serious infections. Doctors therefore recommend specific vaccinations, sometimes preventive antibiotics, and prompt medical attention for any fever afterward.

Recovery. After laparoscopic surgery, many people go home within a few days and return to light activities within a couple of weeks, though heavy lifting and contact sports are usually restricted for longer. After open surgery, recovery tends to take longer. Follow-up imaging may be arranged to confirm that the cyst has not recurred.

Splenic cyst surgery is usually carried out by a general or hepatobiliary surgeon. At Acibadem, this condition is managed within the General Surgery department, working with radiology and, when needed, infectious disease specialists.

Living with splenic cyst and outlook

For most people, the outlook with a splenic cyst is good. Benign cysts do not turn into cancer, and small cysts that are being observed rarely cause problems. If you are under observation, keeping scheduled scan appointments is the main way to stay safe, since growth is usually slow and is picked up on imaging before it causes complications.

If you have a larger cyst that has not yet been treated, your doctor may advise avoiding contact sports or activities with a high risk of a blow to the abdomen, because a large cyst can rupture. Otherwise, normal daily activities, work and travel are usually possible.

After spleen-preserving surgery, most people can return to their usual life and do not need special long-term precautions once healed. Recurrence of the cyst is possible, particularly after partial procedures such as unroofing, so follow-up scans are often arranged for a period of time.

After total splenectomy, lifelong awareness is important. This includes staying up to date with recommended vaccines, carrying a card or wearing a bracelet that states you have no spleen, and seeking care quickly for any high fever, since infections can progress faster without a spleen. With these precautions, many people live full and active lives.

Parasitic cysts require completion of the prescribed antiparasitic course and follow-up blood tests or scans to make sure the infection has cleared. The outcome depends in part on whether other organs, such as the liver or lungs, are also affected.

Frequently asked questions

Is a splenic cyst dangerous?

In many cases a splenic cyst is not dangerous, especially when it is small, nonparasitic and not causing symptoms. The main risks come from very large cysts, which can rupture or press on nearby organs, and from parasitic cysts, which can spread infection or cause allergic reactions if they leak. Your doctor will weigh these factors when deciding whether to observe or treat the cyst.

Can a splenic cyst be cancer?

True splenic cysts are benign and are not cancer. However, some solid or partly solid growths in the spleen can look cyst-like on a scan, so doctors use detailed imaging and sometimes blood tests to make sure the lesion is a simple cyst. If the appearance is unusual, further tests or removal may be advised to rule out other conditions.

What are the most common splenic cyst symptoms?

The most common splenic cyst symptoms are a dull ache or fullness in the upper left abdomen, feeling full quickly when eating, and sometimes pain spreading to the left shoulder. Many small cysts cause no symptoms and are found by chance. Sudden severe pain, fever or a fast heartbeat may signal a complication and needs urgent evaluation.

What causes a splenic cyst to form?

Splenic cyst causes include developmental cysts present from birth, pseudocysts that form after an injury or infarction of the spleen, and parasitic cysts from the echinococcus tapeworm. In many people no clear cause is ever identified. Cysts are not caused by diet or lifestyle.

Does a splenic cyst always need surgery?

No. Small cysts without symptoms are often simply monitored with periodic ultrasound. Surgery is generally considered when a cyst is large, growing, causing symptoms, suspected to be parasitic, or has complications such as infection or rupture. When surgery is needed, surgeons often try to preserve part of the spleen.

How is a splenic cyst diagnosed?

Splenic cyst diagnosis relies mainly on imaging, usually starting with ultrasound and often followed by a CT or MRI scan to define the size, position and internal features of the cyst. Blood tests may be used to check for parasitic infection. Needle biopsy is usually avoided because of bleeding risk and the possibility of spreading infection.

Can a splenic cyst go away on its own?

Some secondary cysts, or pseudocysts, that form after an injury may shrink or disappear over months as the body reabsorbs the fluid. Primary cysts and parasitic cysts do not usually resolve without treatment. Follow-up scans are the only reliable way to know whether a cyst is changing.

When to see a doctor

If you have been told you have a splenic cyst, or you notice persistent discomfort or fullness in the upper left abdomen, it is reasonable to arrange a medical review so that imaging can be performed and a plan agreed. Seek urgent medical care if you experience any of the following red-flag signs, which may indicate rupture, bleeding, infection or a severe allergic reaction:

• Sudden, severe pain in the upper left abdomen or left shoulder
• Pain after a blow, fall or accident involving the abdomen or left ribs
• Dizziness, fainting, pale or clammy skin, or a rapid heartbeat
• High fever with chills or shaking
• Repeated vomiting or inability to keep fluids down
• A rapidly enlarging or increasingly tender lump under the left ribs
• Hives, swelling of the face or throat, wheezing or difficulty breathing
• Any fever at all if your spleen has previously been removed

These symptoms do not always mean something serious is happening, but because the spleen has a large blood supply, complications can progress quickly and are best assessed without delay.