Definition A localized swelling or enlargement in one area of the abdomen. Common Causes Abdominal aortic aneurysm can cause a pulsating mass around the navel or right-upper quadrant. Cholelithiasis can cause a painless, smooth mass in the right-upper quadrant. Diverticulitis can cause a mass that is usually located in the left-lower quadrant. Gallbladder tumor can cause a moderately tender, irregularly shaped right-upper quadrant mass.
Kidney cancer can sometimes cause a mass in the abdomen.
Neuroblastoma , a malignant tumor often found in the lower abdomen, that primarily occurs in children and infants. Ovarian cyst can cause a smooth, rounded, rubbery mass above the pelvis in the lower abdomen. Volvulus can cause a mass anywhere in the abdomen. Ureteropelvic junction obstruction can cause a mass in the lower abdomen. This list is not all inclusive, and the causes are not presented in order of likelihood.