When I saw it on video back in the 1980s, it was much more cringe-inducing.
I seem to recall the lump migrating from the woman's abdomen, causing one of her legs to swell until the skin on her inner thigh was torn open and the guy emerged. She was screaming in agony the whole time. Of course, my memory isn't always reliable.
At any rate, this movie is still plenty gross and disturbing.