I found the following story on the Tea and Skeletons Tumblr.
In 1809, Jane Todd Crawford, a wife and mother of four, was told by her physicians that she was pregnant and seriously overdue, which would explain the large and painful bulge in her stomach. She knew differently ,and sought the treatment of Dr. Ephraim McDowell from 60 miles away (which was an astronomical distance to go to the doctor in those days).
Dr. McDowell showed up and quickly diagnosed her with an ovarian tumor:
Most online sources that talk about this event show this picture, but it can't actually be Jane Todd Crawford, because there are no surviving photographs pre-1826. Camera technology wasn't that good. This must just be a later example of another woman with an ovarian tumor that has been mistakenly associated with Mrs. Crawford and is now misinforming blogs all over the internet. I AM HERE TO SET IT RIGHT. YOU ARE WRONG, INTERNET.
Anyway, Dr. McDowell warned her that no one usually survived surgery this extreme, and that the world's greatest surgeons would believe her case to be impossible. She begged him to at least try, and said she would rather die swiftly than allow the tumor to let her slowly and painfully waste away. He told her that if she was willing to ride all the way to his home, 60 miles away, he would perform the operation there.
"Sure, you can barely walk. How about instead you make a two-day non-stop journey on jolting horseback?" I swear to god he was probably thinking, "Well, that will stop her foolish ideas about having surgery!" But a deal was a deal, and when she showed up on horseback at his house on Christmas morning, he began the procedure.
Keep in mind that there was no anesthesia at this time–the surgery would happen to her while she was awake. To numb the pain as much as they could, she was given a dose of opium. To keep her still, McDowell had several attendants hold her down. She apparently sang hymns and recited Psalms during the operation.
Through a 9-inch incision, Dr. McDowell removed a 22.5 lb. tumor (definitely not a baby, then! In your face, local practitioners!) and stitched her up. The entire thing, amazingly, only took 25 minutes from start to finish. She stayed at his house for observation, since it was very likely that she would die from infection. However, McDowell was notoriously meticulous and didn't believe in the slipshod hygiene of other doctors of his day. During the operation, he was observed obsessively removing any extraneous blood he had spilled into her body cavity and gingerly washing her intestines with clean, warm water before sewing her up.
She did very well her first few days after the surgery, and when Dr. McDowell checked in on her on the fifth day, he said, "I visited her, and much to my astonishment found her making up her bed." That very day she got back on her horse and rode the 60 miles back home.
She lived another 32 years. This was the first successful removal of an ovarian tumor in the world, and the eventual publication of his results encouraged better hygiene practices for doctors.