What Does A Lump On In Upper Leg Indicate?

My husband just found a large lump on the top of his right leg near the crease. It is red and approximately 4 long and 1 1/2 wide. It is raised quite a bit. It does not itch and is not painful. However, he has had quite a bit of lower abdominal pain the last 2 days. We are wondering what it might be.