Panniculus is a meical term describing a dense layer of fatty tissue growth, usually in the abdominal cavity. It can be a result of morbid obesity and can be mistaken for a tumor or hernia. Abdominal panniculus (the "apron" in layman's terms) can be removed during abdominal panniculectomy, a type of abdominoplasty. A panniculus can also be the result of loose tissues after pregnancy or massive weight loss.