The 48-year-old Argentine saw his side produce a stirring second-half fight-back from three goals down to draw 3-3 with Liverpool in the Champions League on Tuesday, and Spanish media reported that he told his players about the illness at half-time.
The football world has sent messages of support on social media, with Sevilla captain Nico Pareja posting an open letter from the whole squad to the coach and fans on Twitter.
"We wish him a full and speedy recovery. We pass on to him something that has been the mark of this club for a long time: It is said we never surrender. We'll all be there to make sure of that," read the letter.
"Gaffer, you have more than enough courage to get through all of this. You've won our respect and affection and we want to let you know you can count on your team and thousands of people that will stand by you and help you in this process. You are not alone in this battle."
Former Sevilla and current Paris St. Germain coach Unai Emery, La Liga and clubs including Real Betis and Celta Vigo have been among those to offer Berizzo their support and solidarity.
Earlier on Wednesday Sevilla published a statement explaining the coach had been diagnosed with a malignant tumour and would have treatment after further tests.
"Sevilla's medical team reports that the first team coach, Eduardo Berizzo, has been diagnosed with an adenocarcinoma in the prostate," said the club.
"Future examinations will lead to a decision over what steps to follow in his treatment. Sevilla wants to offer their maximum support to the coach in these moments and wish him a quick recovery."
Berizzo took over at the Ramon Sanchez-Pizjuan in the summer after spending three seasons at Celta Vigo, who he also played for between 2001 and 2005.
(Reporting by Rik Sharma; Editing by John O'Brien, Neville Dalton)
