ROME — Silvio Berlusconi’s legal woes worsened Wednesday when a Milan appeals court upheld his four-year jail sentence for tax fraud involving multimillion-dollar Hollywood deals inked by the former Italian prime minister’s Mediaset TV empire.

Berlusconi does not face immediate imprisonment. The media-mogul-turned-pol has one final appeal left, to the country’s Court of Cassation, before the statute of limitations expires on the case in July.

The billionaire tycoon has been convicted before in a long series of trials over two decades, but his past verdicts have always been overturned or taken so long to reach that the statute of limitations has expired.

The trial stems from €470 million ($678 million) in movie rights purchased by Mediaset from Hollywood studios, including Paramount and Fox, through offshore companies during the 1990s to allegedly evade taxes and create a slush fund. Berlusconi’s first conviction in this trial came in October.

Berlusconi has always maintained his innocence. He recently claimed the Milan magistrates are “out to eliminate a political adversary” and tried, unsuccessfully, to have the trial moved to the nearby city of Brescia.

Berlusconi is also on trial in Milan on a separate charge of having sex with an underage girl, which he also denies.

A verdict in this trial, also underway in Milan, is expected this month.

The three-time former prime minister now faces his toughest legal challenge weeks after making a stunning political comeback. It comes as his Mediaset is beginning to bounce back in the first quarter of 2013 after posting €287 million ($374 million) in losses for fiscal 2012, its first annual net loss ever.

Pundits say the ruling could spark tensions within the Italian coalition government in which the conservative, Berlusconi-led PDL is a key partner, though Berlusconi himself has no official role. Berlusconi’s political weight and Mediaset’s market performance are widely considered to be connected.

While it is still possible that the 76-year-old known as the “Teflon Tycoon,” will remain unscathed, his odds of beating the charges have become slimmer.