If you consider hypochondria (or somatasensory, if you want to be PC) pathological lying...there was a girl who went to my highschool who always had SOMETHING. Hypoglycemia, dislexia (or "lysdexia" as she called it), ADHD, and high or low blood pressure (she could never remember which, so it kinda changed depending on the day...), plus sprains (which she would either wear braces on, or tape up with hockey tape), rug burns (she was a tumbler and would frequently land on her head/face), and anything else under the moon.
Thing is about hypocondriacs - it takes NOTHING to convince them they have some new disease. So, when my friend and I started listing off the "symptoms"

of nymphomania, she decided she had it, and announced it to whoever would listen. (Ok, so it was mean of us, but I would research a disease a LITTLE BIT myself before I announced to everyone, you know?) So after that died down we tried it again with necrophilia... You know the saying "Fool me once, shame on you, fool me twice, shame on me..."? Apply here.