Polle syndrome

Etymology
Coined by Burman and Stevens, from the then-common belief that Baron Münchhausen's second wife gave birth to a daughter named Polle which the baron declared was not his. The term fell out of favour after 1984, when it was discovered that Polle was not the baby's name, but that of her mother's hometown.

Noun

 * 1) Münchausen syndrome by proxy