Diagnosis:

Doctors may suspect that the spleen is enlarged when people complain of fullness or pain in the upper left portion of the abdomen or back. Usually, doctors can feel an enlarged spleen during a physical examination. An x-ray of the abdomen may also show that the spleen is enlarged. In some cases, ultrasonography or computed tomography (CT) is needed to determine how large the spleen is and whether it is pressing on other organs. Magnetic resonance imaging (MRI) provides similar information and also traces blood flow through the spleen. Other specialized scanning devices use mildly radioactive particles to assess the spleen's size and function and to determine whether it is accumulating or destroying large numbers of blood cells.

Blood tests show decreased numbers of red blood cells, white blood cells, and platelets. When blood cells are examined under a microscope, their shape and size may provide clues to the cause of the spleen enlargement. An examination of bone marrow may show cancer of the blood cells (such as leukemia or lymphoma) or an accumulation of unwanted substances. Blood protein measurement can determine whether other conditions are present that can cause the spleen to enlarge, such as amyloidosis, sarcoidosis, malaria, kala-azar, brucellosis, and tuberculosis. Liver functions tests help determine whether the liver is also diseased.

Doctors cannot easily remove a sample of the spleen for examination because inserting a needle or cutting spleen tissue may cause uncontrollable bleeding. If an enlarged spleen is removed during surgery to diagnose or treat certain diseases, the spleen is sent to a laboratory, where the cause of enlargement can usually be determined.