Barcelona coach Tito Vilanova will have surgery on his parotid gland on Thursday before undergoing approximately six weeks of chemotherapy, the club have confirmed.
The 44-year-old, who had surgery to remove a tumour on the same gland last November, is due to remain in hospital for "three to four days" after the operation.
"In monitoring the process of his parotid gland, an extension of the pathology was detected, requiring surgical treatment on Thursday," the statement on fcbarcelona.es read.
"An extension of the pathology has been detected in [Vilanova's] parotid gland. The manager requires surgery which he will undergo this Thursday. He is expected to remain in hospital for three to four days.
"After the surgery, Francesc 'Tito' Vilanova will undergo chemotherapy and radiation treatment for approximately six weeks. During this time, and depending on how well he recovers, Vilanova's treatment may be compatible with his work life.
"Keeping in line with the patient's wishes, we urge respect and privacy during this process."
Vilanova, who replaced Pep Guardiola this summer, has enjoyed a superb start to his tenure in the hotseat, helping Barcelona establish a nine-point lead at the top of the Primera Division standings after winning 15 of their opening 16 games while drawing the other.
Barcelona are also through to the knockout stages of the UEFA Champions League and hold a 2-0 first-leg lead over Cordoba in their Copa del Rey last-16 tie.
Surgery will definitely rule Vilanova out of Saturday's trip to Real Valladolid.
A host of Spanish clubs and players expressed their support before the official announcement, including rivals Real Madrid.
A statement on the Madrid website read: "Real Madrid want to express their support and best wishes for the coach of FC Barcelona, Tito Vilanova, and wish him a very rapid recovery. Real Madrid offer their support to his club and to all his family."
Club president Sandro Rosell expressed his "unconditional support" for Vilanova at a specifically-convened press conference, in which he was flanked by on-field leaders Carles Puyol, Xavi, Andres Iniesta and Victor Valdes.
Rosell revealed assistant coach Jordi Roura would take charge of the first team, while Vilanova underwent his treatment.
The club has, however, left the door open for Vilanova to return to the touchline during his recovery, saying that his "treatment may be compatible with his work life".
That decision is set to be made after surgery but for now Rosell offered the club's full support for Vilanova and his young family.
"Tito is strong, very strong. He's shown us that and we're convinced he'll back with us very soon," he told a press conference.
"We want to express our unconditional support to Tito and his family.
"We thank everyone for their support. We have complete confidence in the team. The club is very strong and united, we're capable of overcoming adversity."