The case was filed in Philadelphia last month by Williamsport attorney Bret Southard, whose client was identified only by his initials, The Centre Daily Times (http://bit.ly/WcGbY8) reported.
The lawsuit claims Sandusky abused the boy during a shopping trip in 2008 or 2009, and after they attended a Penn State game in 2008 against Coastal Carolina University.
The trip would have come around the time law enforcement officials began investigating Sandusky in late 2008, based on a complaint involving a student in central Pennsylvania. They charged him in 2011.
Southard told the newspaper his client represents a new case. The lawsuit seeks $550,000, along with punitive damages and interest. Penn State previously settled 26 cases for nearly $60 million.
The lawsuit describes the boy as a participant in The Second Mile, the charity for at-risk children Sandusky founded, the newspaper reported.
Second Mile official David Woodle said the charity would "engage with them and try just to understand what's there and take it through the legal process." He said The Second Mile now exists only as the owner of real estate that is currently for sale.
A Penn State spokesman declined to comment, and messages left by The Associated Press for Southard and Sandusky's legal team late Wednesday were not immediately returned.
Sandusky was convicted two years ago of sexual abuse of 10 boys and is serving a lengthy state prison sentence.
The lawsuit said the accuser was among the boys listed as Second Mile participants on a document taken from Sandusky's home during the investigation. Some of the names had check marks next to them.
"There was such a mark next to plaintiff's name. The (state police) then contacted (his) parents," the lawsuit said.
Information from: Centre Daily Times, http://www.centredaily.com