The Spain international was suffering from headaches and back pain earlier this month and underwent a CAT scan on May 14 which revealed a tumour.
Torrecilla, 26, had surgery earlier this week in Pamplona and left hospital on Thursday to begin her recovery, the club confirmed.
"Everything went fantastic, the operation was a success and everyone is very happy with my progress," Torrecilla said in an Instagram video.
"The tumour was not that small and I may have had it for some time. I can tell you that I never, never imagined that something like this could happen to me but it has. When the doctors saw the scan they thought that it was benign which was positive but you can imagine what it meant for me to have this. But there was only one path."
The former Barcelona player, who joined Atletico last summer, thanked her club for its support.
"Atletico has done the impossible for me," she said. "Now I can't wait to start my recovery.
"I've decided to make this public because it's important for those people that have illnesses and those that battle daily hurdles to know that challenges can be overcome. You can overcome anything, all you need is will and strength. I have overcome a tumour and I'm delighted. If before I used to live life to the fullest, now I'm going to do double that. I hope this is the beginning of something great."
The Spanish Football Federation wished Torrecilla a speedy recovery.
"We hope to see her as soon as possible on the pitch representing Spain again," it said in a statement.
Torrecilla, who has made 63 appearances for Spain and played in all four of their games at the 2019 World Cup.