The term lymphoma refers to cancer of the lymphoid system, which is a major component of the immune system. The body's lymphoid system is composed of several organs, including the spleen, thymus and lymph nodes, tiny organs found in the groin, armpit, neck and other areas throughout the body. Lymphoma develops when cells of the immune system known as lymphocytes begin rapidly growing and multiplying. These out-of-control cells can cause many different symptoms, some of which may be located in the abdomen.
One common abdominal symptom of lymphoma is swelling. In some patients with lymphoma, the vessels that transport fluid in between different lymphoid organs may become obstructed by the excess growth of cancerous cells. If lymph vessels in the abdomen become blocked, this can cause fluid to accumulate in the abdomen, which is called ascites, explains Lymphomation.org. The excess fluid is often first felt in the sides of the abdomen. In severe cases, it can cause the belly button to push out, a condition known as umbilicus eversion. The swollen abdomen may become tender or painful.
One rare type of lymphoma known as Burkitt's lymphoma, is caused by rapid, uncontrolled growth of a specific type of immune cells called B cells. In Burkitt's lymphoma, the rapidly multiplying B cells usually accumulate specifically in the abdomen, within the lymph nodes and other organs. In this case, swelling is caused by the excess number of immune cells, as opposed to excess fluid that causes ascites. The swelling caused by cells can also cause pain and tenderness in the abdomen. In some cases, the excess cells may also seep into the small intestine, which can cause intestinal blockages and bleeding, reports the Merck Manuals.
Some, but not all, cases of lymphoma may cause additional abdominal symptoms. Pain and swelling in the abdomen may cause patients to lose their appetite, reports the Mayo Clinic. Chronic loss of appetite can lead to extreme, unintentional weight loss. Nausea and vomiting may also result from disturbances in the abdomen. Some patients with lymphoma may also suffer from recurring constipation.