Abdominal Abscess: What’s Causing the Pain in My Tummy? What is an abdominal abscess? An abscess is a pocket of inflamed tissue filled with pus. Abscesses can form anywhere on the body (both inside and outside). They’re most commonly found on the surface of the skin. An abdominal abscess is a pocket of pus located in the abdomen. Abdominal abscesses can form near the inside of the abdominal wall, at the back of the abdomen,…"Abdominal Abscess: What’s Causing the Pain in My Tummy?"