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. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as location, quality, time course, aggravating factors, relieving factors, and associated complaints.