Abdominal mass

An abdominal mass is a lump, bulge, or firm area in or on your belly. It may come from the abdominal wall, the organs inside the abdomen, or the bowel. Some masses are visible, while others are noticed only when you touch the area or have a medical examination.

“Mass” describes what is felt or seen. It is not a diagnosis and does not mean the lump is cancer. Common explanations include a hernia, constipation, or a harmless fatty lump. The possible causes also depend on where the mass is, whether it changes with movement, and whether you have other symptoms.

A new or unexplained abdominal mass should usually be checked, even if it is not painful.

An abdominal mass may feel soft, rubbery, firm, or hard. It may have clear edges or feel more like general fullness. It can stay in one place or become more noticeable when you cough, strain, stand, or lift something.

You may notice:

• A bulge under the skin
• One side of the abdomen looking fuller
• A lump that appears when standing and flattens when lying down
• Tenderness or pressure around the mass
• Bloating, constipation, nausea, or changes in appetite
• A pulsing sensation in the middle of the abdomen

Do not repeatedly press or deeply massage the area to test it. This may cause pain and cannot reliably show what the mass is.

A hernia happens when tissue pushes through a weak area in the muscle wall. It often causes a bulge near the groin, navel, or a previous surgical scar. The bulge may appear with coughing or straining and disappear when you lie down.

Constipation can cause firm stool to collect in the bowel. This may feel like fullness or a firm area, often with fewer bowel movements, hard stools, or difficulty passing stool.

A lipoma is a non-cancerous lump made of fatty tissue. It is usually soft, slow-growing, and movable under the skin. Lipomas are often painless.

Other possible causes include:

• An enlarged organ, such as the liver, spleen, or kidney
• A full or enlarged bladder
• Uterine fibroids, which are non-cancerous growths in the womb
• An ovarian cyst
• Pregnancy
• Inflammation, infection, or a collection of pus called an abscess
• A cyst or another growth in an organ or soft tissue

Less commonly, an abdominal mass can be caused by cancer. Features such as ongoing growth, unexplained weight loss, reduced appetite, blood in the stool, or persistent changes in bowel habits need medical assessment, but they do not confirm any one cause.

Book a routine appointment if you find a new abdominal lump that has no clear explanation. Arrange review if it lasts, enlarges, returns, or causes ongoing discomfort. A painless mass should still be checked.

Seek same-day medical care if the mass:

• Becomes painful or very tender
• Is accompanied by fever or repeated vomiting
• Feels firm and no longer flattens when it previously did
• Comes with increasing abdominal swelling
• Occurs with difficulty passing stool or gas
• Has red, purple, or dark skin over it

These features may occur when a hernia becomes trapped, the bowel is blocked, or infection is present.

Call emergency services for sudden, severe abdominal or back pain, especially with a pulsing abdominal mass, fainting, severe weakness, pale or sweaty skin, or trouble breathing. Also seek emergency help for severe pain with repeated vomiting, a rigid abdomen, or collapse.

A clinician will ask when you first noticed the mass, whether it changes with coughing or position, and whether it is growing. They may also ask about pain, bowel and bladder changes, previous surgery, menstrual history, possible pregnancy, appetite, and weight changes.

During an examination, they may check the mass while you are lying down and standing. They may gently feel whether it is in the skin, abdominal wall, or deeper inside the abdomen.

Depending on the findings, tests may include:

• An ultrasound, which uses sound waves to make images
• A CT or MRI scan for more detailed images
• Blood or urine tests
• A pregnancy test when relevant
• Tests of the bowel or other organs if symptoms point to them

Not every abdominal lump needs all of these tests.

Treatment depends on the cause. Constipation may improve with fluids, gradual increases in fibre, physical activity, or medication recommended by a healthcare professional. Do not assume constipation is the cause if the lump is new, painful, or persistent.

A hernia may be monitored or repaired with surgery, depending on its location, symptoms, and risk of complications. Do not force a painful or firm hernia back into place. Avoid heavy lifting until it has been assessed if lifting makes the bulge appear or hurt.

Lipomas often need no treatment unless they are painful, growing, or affecting movement. Infections may need antibiotics or drainage. Cysts, enlarged organs, fibroids, and other growths are treated according to their cause and symptoms.

Until you are assessed, note whether the lump changes with meals, bowel movements, coughing, standing, or lying down. Avoid repeated pressing and do not start laxatives if you have severe pain, vomiting, or cannot pass gas.

Some abdominal masses disappear when a temporary problem, such as constipation, settles. A hernia may come and go but usually does not permanently heal by itself. Lipomas and other non-cancerous growths may remain unchanged for years.

Follow-up may involve watching for changes, arranging imaging, or referring you to a specialist. Seek an earlier review if the mass grows, becomes painful, or new symptoms develop.

Can gas cause an abdominal mass?

Gas usually causes widespread bloating rather than one clearly defined lump. A localised or persistent mass should not be assumed to be gas.

Is an abdominal mass always serious?

No. Hernias, constipation, and fatty lumps are common explanations. However, the cause cannot always be identified by touch, so a new unexplained mass should be assessed.

Why does the lump disappear when I lie down?

Some hernias become less noticeable when pressure inside the abdomen falls. A lump that changes with position still needs assessment, particularly if it becomes painful or stops flattening.

Can I wait if the lump does not hurt?

A short wait for a routine appointment is generally reasonable if you otherwise feel well. Do not ignore a lump that persists, grows, or is accompanied by weight loss, bowel changes, or reduced appetite.