American Mary was the horror movie from the Soska sisters. It featured Kathrine Isabella as the title character. A surgeon who goes out on her own.
The movie was quite good. It was a cross between the French Extreme horror and old fashioned Cronenberg body horror. Sort of like a remash of the Jermy Irons film Dead Ringers.
This post is going to focus on the Halloween outfits you can wear if you're inspired by the film.
Katherine Isabella's wardrobe is pretty simple and consistent. She wears a sort of domination, fetish inspired outfit. A crisp white shirt, black stockings, black skirt, black high heels, and a black leather/rubber apron.
So, if you're going for the American Mary look here are some suggestions:
Number 1 Item: Leather/Rubber Apron
This is the most important aspect of the American Mary costume. You most likely have the white blouse, dark skirt and high heels. This is the one thing---along with the surgeons knife---they you will need to pull off the costume.
Number 2: White Dress Blouse
If you don't have a white dress blouse, then this is a great one to get. It is a classic cut and you can wear it for lots of events...not just your costume party.It is a quarter sleeve...so you don't have to roll up the sleeves to get the American Mary look. Rolled up sleeves look great on Men, but women want clean lines for dress shirts and this looks much better.
Number 3: Black Stockings
The photo here presents them as sexy stockings, and they are, but when you wear them with a dark skirt, they work wonderfully as really great color combinations.
Number 4: Black High Heels
If you don't have a pair of Black high heels, now's your chance to get them. It's important to get high heels that are high enough. You want something that has a sexy and slightly fetish bent. But, you don't want to get something that is junk. You want quality. That's why I recommend Jessica Simpson brand. They are high quality and feel comfortable.
Number 5: Black Skirt
This is essential as well. If you don't have s slim black skirt, then this is a good choice.
The Final Note: The Cleaver
The whole attitude of American Mary is revealed in the photo of the Cleaver wielding Mary. She has the most brutal surgeons instrument. Here is a safe replica you can use for your Halloween party. 
Of course....if you haven't seen the movie, definitely do so. It's very cool.
