A lump in the abdomen is a soft bulge of tissue or a small, local area of swelling in the belly area.

See also: Abdominal mass

Abdominal hernia; Hernia - abdominal; Abdominal wall defects; Lump in the abdominal wall; Abdominal wall mass

Most often, a lump in the abdomen is caused by a hernia. An abdominal hernia occurs when there is an area where the muscles are weak. This allows the internal organs to bulge through the abdominal wall. A hernia may not appear until after you strain, lift something heavy, or have a prolonged period of coughing.

There are several types of hernias, based on where they occur:

• Inguinal hernia appears as a bulge in the groin or scrotum. This type is more common in men than women.
• Incisional hernia can occur through a scar if you have had abdominal surgery.
• Umbilical hernia appears as a bulge around the belly button. It occurs when the muscle around the navel doesn't close completely.

Other causes of the lump in the abdominal wall include:

• Hematoma (collection of blood under the skin after trauma)
• Lymph nodes
• Lipoma (collection of fatty tissue under the skin)
• Undescended testicle
• Tumor of the skin or muscles

Malangoni MA, Rosen MJ. Hernias. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 44.

Turnage RH, Richardson KA, Li BD, McDonald JC. Abdominal wall, umbilicus, peritoneum, mesenteries, omentum, and retroperitoneum. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 43.