Rowen Foster was a background DHARMA Initiative member in LOST. She appeared in "The Man Behind the Curtain" as one of Ben's classmate.
Rowen's costome
In Lost: The Auction, the costume Rowen worn was auctioned along with 2 other DHARMA children costumes, and from the picture of the item in the catalog, Rowen's full name was seen written on the collar of the costume.