The 26-year-old Slovakian has made 262 appearances for the Serie A side after signing from Brescia in 2007 and De Laurentiis tonight described him as "a great player who honours the Napoli shirt".
Via his official Twitter account, the Azzurri chief added: "It is a shirt that Marek is happy to honour. We have renewed his contract, extending it until 2018."
De Laurentiis then posted a picture of himself linking arms with the attacking midfielder, who has notched 70 goals for Napoli.
Opening his unofficial account for the Campanian club on Friday night was Argentinian striker Gonzalo Higuain, who hit the winner in a 2-1 friendly victory over Benfica in Naples following his reported 40million euro switch from Real Madrid.