Scifi series from the 90:s i think.

Hi. I have some vague memories of a tv series shown here in sweden in the 90:s. It was in english and all i seem to remember was something about a alien(i think) child/teenager living on eart, they were being protected by some neighbor or similar in disguise. The alien had extra organs(never got sick etc) and i seem to remember a "swordfight" between an old woman using a cane/umbrella and someone else using a (possible laser) sword.