Colon Mass, Adult

ExitCare ImageA mass is a lump that either your caregiver found during an examination or you found before seeing your caregiver. The colon is a major part of the large intestine. There are many possible reasons why a lump has appeared. Testing will help determine the cause and the steps to a solution.


Before complete testing is done, it may be difficult or impossible for your caregiver to know if the lump is truly in the colon or comes from one of the organs that are next to the colon. Problems in the liver, gallbladder, pancreas, kidney, small intestine, uterus, and ovaries can also lead to a lump that might seem to be in the colon.

If testing shows that the mass is in the colon, there are still many possible causes, including:

  • Tumors and cancers. These problems are relatively common and are the greatest source of worry for patients. Cancerous lumps in the colon may be due to cancers that started in the colon or due to cancers that started in other areas and then spread to the colon. Many cancers are very treatable when found early.

  • Noncancerous tumors and masses. There are a large number of common and uncommon noncancerous problems that can lead to a mass in the colon. Before testing or surgery, it may be impossible to tell the difference between this problem and a cancer.

  • Infection. Certain types of infections can produce a mass in the colon. The infection might be caused by a bacteria. The treatment might include medicine that kills bacteria (antibiotics). Masses from infection can also be caused by certain viruses, fungi, and parasites. If infection is the cause, your caregiver will be able to determine the type of germ responsible for the mass by doing testing.

  • Inflammatory bowel disease. These are diseases thought to be caused by a defect in the immune system of the intestine. Two inflammatory bowel diseases are ulcerative colitis and Crohn disease. They are lifelong problems with symptoms that can come and go. Not all patients with these diseases will develop a mass in the colon.

  • Blood vessel problems. A partial block of the blood supply to the intestine can lead to swelling of the wall of the colon. If this happens over and over again, a mass can develop.

  • Past surgery. If there has been colon surgery in the past and there is a lot of scarring that forms during the process of healing, this can eventually feel like a mass when examined by your caregiver. As with the other problems described above, this may or may not be associated with symptoms or feeling badly.

  • Volvulus. This is a condition where the colon twists on the organ or tissue that supports the colon (mesentery). It occurs most often near the very end of the colon and is a common cause for blockage of the colon. Along with a mass, there are almost always symptoms of pain, constipation, and bloating with this condition.


In people with a colon mass, there may be a large variety of associated symptoms, including:

  • No symptoms, other than the appearance of the mass itself.

  • Cramping, nausea, or diarrhea.

  • Fever, vomiting, or weakness.

  • Abdominal, side, or back pain.

  • Weight loss.

  • Constipation.

  • Bleeding from the rectum.


Because of the large number of causes of a mass in the colon, your caregiver will ask you to undergo testing in order to get a clear diagnosis in a timely manner. The tests might include some or all of the following:

  • Blood tests. A blood test may include a blood count; a measurement of common minerals in the blood; kidney, liver, and pancreas function; and others.

  • X-rays. Plain X-rays and special X-rays may be requested.

  • Ultrasonography. This is a test that uses sound waves. The sound waves bounce off the organs like an echo. The echoes are "heard" by a device called a transducer. The transducer converts the sounds into an electronic picture of the organ or structure. Your caregiver will examine this picture.

  • CT scan and MRI imaging. Each test can provide additional information about the different characteristics of the mass and can help to develop a final plan for diagnostics and treatment. If cancer is suspected, these special tests can also help to show any spread of the cancer to other parts of the body.

  • Colonoscopy. This is a special exam of the inside of the colon with a slim, flexible, lighted tube. This tool allows your caregiver to get a direct look at the mass from the inside of the colon. Sometimes, this allows removing a very small piece of the mass (biopsy). This piece of tissue can then be examined in a lab. Looking at the tissue in this way will frequently lead to a clear diagnosis.

  • Surgery. Sometimes, a diagnosis can only be made by carrying out an operation and obtaining a biopsy sample. Many times, the biopsy sample is obtained and the mass is removed during the same operation.

These are the most common ways for determining the exact cause of the mass. Your caregiver may recommend other tests that are not listed here.


Treatments can only be recommended after a diagnosis is made. Your caregiver will discuss your test results with you, the meanings of the tests, and the recommended steps to begin treatment. The caregiver will also indicate whether you need to be examined by specialists as you go through the steps of diagnosis and while a treatment plan is being developed.


  • Test preparation. Carefully follow instructions when preparing for certain tests. This may involve medicines that clean out the intestines before colonoscopy, fasting before certain blood tests, or drinking special "contrast" fluids that are necessary for CT scan and MRI images.

  • Medicine. Your caregiver may prescribe medicine to help relieve symptoms while you undergo testing. It is important that your current medicines (prescription, nonprescription, herbal, or vitamins) be kept in mind when new prescriptions are recommended.

  • Diet. There may be a need for changes in diet to help with symptom relief while testing is being done. If this applies to you, your caregiver will discuss these changes with you.


  • You cannot hold down any of the recommended fluids used to prepare for tests such as colonoscopy, CT scan, or MRI.

  • You feel that you are having trouble with any new prescriptions.

  • You develop new symptoms (such as pain, vomiting, diarrhea, or fever) or other problems that were not present at the last exam.


  • You vomit bright red blood or material that looks like coffee grounds.

  • You have blood in your stools, or the stools turn black and tarry.

  • You have a fever.

  • You develop easy bruising or bleeding.

  • You develop pain that is not controlled by your medicine.

  • You feel worsening weakness, or you have a fainting episode.

  • You feel that the mass has suddenly gotten larger.

  • You develop severe bloating in the abdomen.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.