The 32-year-old confirmed on social media that he underwent emergency surgery to remove the tumour and that he is currently in recovery.
"Sorry, I haven’t been around much, It has been the toughest few weeks of my life," Enrique wrote on his official Instagram account.
"Within the space of one month I have found out the news that I have a rare brain tumour and had surgery to have it removed, I am now in recovery and so thankful. Life is too precious."
Enrique spent a total of nine years playing in the Premier League. The defender left Valencia in favour of a move to Newcastle United in 2007 for just under £8m, going on to move to Anfield four years later for a similar price tag.
Enrique confirmed in his interview with Marca that he had spent two days at St George's Hospital, who specialise in neurology in London. The former Spain Under-21 international is also now forced to wear a patch as the tumour was located just behind his eye.
He said: "All this makes values more life, soccer players live in a bubble, it's an unreal life, you lose yourself and you think you're invincible." When you play soccer, your head does not check it.
"I want to thank my girlfriend, my parents and my brothers, as well as Dr. Simal, his team and La Fe hospital."
Enrique made a total of 161 appearances in the Premier League, scoring two goals and claiming 15 assists. Both his goals came during the 2012/13 season, coming in big wins against Wigan and Swansea at Anfield.