RHINELANDER, WI (WSAU) -  On Friday, 17-year-old Leanna Kossack of Rhinelander enjoyed a day dedicated to her. Mayor Dick Johns declared it Leanna Kossack Day, as friends and family held a benefit for her.

On Monday afternoon, Kossack passed away.

Kossack suffered from a rare form of cancer called Undifferentiated Sarcoma, which caused a tumor the size of a softball to encompass her spine.

She was a junior at Rhinelander High School