European captain Carin Koch made the announcement on Sky Sports TV.
All four players were on the squad that beat the Americans in a record 18-10 rout at Colorado Golf Club two years ago, becoming the first European team to win the Solheim Cup on American soil.
The Europeans will be looking to win the Solheim Cup for the third consecutive time when the matches are played Sept. 18-20 at St. Leon-Rot Golf Club outside Heidelberg, Germany.
Matthew was named to her eighth European Solheim Cup team.
Hedwall was the first player to go 5-0 in the history of the Solheim Cup in that rout in Colorado.
Masson gives Germany two homegrown players to root for, joining Sandra Gal, who made the team on points.
Icher was named to her third team.
“We’ve got a great mixture of youth and experience, which really excites me as captain,” Koch said. “Each of our players has a role to play, and I have team of stars. Now that the team is finalized, we can all have full focus for the week in Germany. I can’t wait to see the players together at Golf Club St Leon-Rot.”
They join the eight players who qualified for the team: Sweden’s Suzann Pettersen and Anna Nordqvist, France’s Gwladys Nocera, England’s Charley Hull and Melissa Reid, Spain’s Azahara Munoz and Carlota Ciganda and Germany’s Gal.