Bowen's disease is a precancerous form of SCC sometimes referred to as squamous cell carcinoma in situ. It develops slowly and is easily treated. The main sign is a red, scaly patch on the skin that may itch. It most commonly affects elderly women and is often found on the lower leg.
Noelle and Cali aren't the only twins to have played one child character in Friends. Double vision: Ross' cheeky son Ben (pictured), from his first marriage to Carol, was also played by twins, Dylan and Cole Sprouse, who are now 22.
Felix gained a girlfriend in the third season, Miriam Welby (played by Elinor Donahue), and they lasted into the fifth season, presumably breaking up before Felix remarried Gloria in the series finale. Christopher Shea appeared in three episodes of the first season as Philip, Felix and Oscar's 11-year-old neighbor.