Munchausen's Syndrome (sometimes Munchausen Syndrome), pronounced mun/chau/zen.
A factitious disorder named after the baron of Munchausen who was an 18th century German soldier. A book in his name, Baron Munchausen's Narrative of His Marvellous Travels and Campaigns in Russia, was revealed some 40 years later to have been written by someone else, and his name came to be synonomous with telling a lie and getting away with it.
A Munchausen's sufferer will often have a very detailed knowledge of medicine, particularly diseases and surgical procedures. S/he will often 'pick' a disease or physical disorder from a medical textbook and exhibit the symptoms of that disorder. Subjective and hard-to-confirm symptoms like pain are most common. Typically, the patient will undergo several rounds of exploratory surgery and often quite invasive procedures in an attempt for a cure. Some patients will sabotage their treatment in an attempt to cause complications, others will be "cured" until they start to feign symptoms of another illness. Some sufferers actually go to lengths to contract a genuine disease or injure themselves so they can be treated.
Munchausen's sufferers require psychiatric help and the condition is known to be very difficult to cure.
Not to be confused with Munchausen by Proxy Syndrome, where the sufferer harms another person such as a child.