A former top administrator and principal at String Theory Schools has filed a federal suit alleging the charter operator discriminated against her and wrongfully terminated her because of her age.

Gail H. Avicolli contends that shortly after the School Reform Commission renewed the five-year operating agreement for the Philadelphia Performing Arts Charter School in January, 2014, founder Angela Corosanite and son Jason, the chief operating officer, embarked on a campaign to remove the woman who was "the face" of the String Theory charters.

Avicolli, then 67, said Angela Corosanite repeatedly shouted at her, "Do you know how much your health insurance costs me because of your age?"

Avicolli is suing Corosanite, String Theory Schools, and the Performing Arts school. String Theory manages the South Philadelphia school. Corosanite and the charter organizations' attorney could not be reached for comment Monday.

Corosanite hired Avicolli in August 2005 as principal of the school, which then had less than 450 students. By the time Avicolli was promoted to superintendent and chief academic officer in 2012, Corosanite was involved with four charter campuses with more than 1,400 students and had created String Theory to manage the schools.

The complaint alleges that Corosanite created a hostile work environment, discriminated against Avicolli based on her age and gender, and retaliated when she pressed to have the same health coverage and benefits she had in prior contracts.

According to the suit, Avicolli had to take medical leave and was hospitalized in spring 2014 to deal with severe headaches and other health issues related to job stress.

After her doctors cleared Avicolli to return to work, she was terminated on June 30, 2014, when school officials told her that her position had been eliminated because of budget cuts. String Theory, however, continued to hire new employees and created new administrative positions, the suit said.