The 77-year-old former premier was sentenced last year to seven years in jail and banned from holding public office for having sex with "Ruby the Heart Stealer" at what prosecutors described as erotic parties at his luxury home.
A definitive guilty verdict could hamper Berlusconi's liberty: while Italy tends to be lenient towards over-70s found guilty of non-violent crimes, the billionaire would no longer be eligible for community service and would likely be sentenced to house arrest.
The media mogul has been forced to drop the lawyers who defended him in the trial, after they were caught up in a witness corruption probe launched amid allegations of bribes paid to girls taking the stand to defend Berlusconi.
Forty-five people are under investigation, including Berlusconi, his lawyers, Ruby and several other young women.
The three-time premier has repeatedly denied having sex in 2010 with then 17-year-old exotic dancer Ruby – whose real name is Karima El-Mahroug – during parties that witnesses said featured nudity and strippers dressed as nuns.
El-Mahroug told the first trial about attending "sensual" soirees that invitees nicknamed "bunga bunga" in a discotheque at Berlusconi's villa, saying she was paid €2,000 or €3,000 euros a night – but she also denied having sex with the tycoon.
Berlusconi says they were "normal dinner parties" followed by "burlesque contests".
He was also found guilty of abusing his powers by having an aide call a police station to press for the busty glamour girl's release from custody when she was arrested for suspected theft.
His defence claimed he believed El-Mahroug was the niece of former Egyptian president Hosni Mubarak and wanted to avoid a diplomatic incident, but prosecutors insisted that was a bid to conceal their relationship.
The punishment was suspended during the appeals process, which is expected to last months. The first appeal hearing was expected to be dedicated to technical issues.
A verdict is expected in September or October, after which the case is likely to go to the Supreme Court, according to Italian media reports.
Berlusconi – who was definitively convicted for tax fraud last year – was absent from court because he was performing his community service, which involves helping out weekly in a hospice for Alzheimer's patients.