Wet roads played their part over the final few fraught kilometres as one rider fell in the centre of the pack, bringing down others either side of him, including Bennati.
"He is to have a scan on his hip this evening," medical staff announced.
The crash left a group of 20-30 riders on their own to fight for the stage win, with the rest blocked by the mass of bodies and bicycles across the road.
Bennati is currently Lampre's leader in the sprints. Should he be unable to continue the race, his role would be passed on to Danilo Napolitano, who won stage nine of this year's Giro d'Italia.