I did a little google search on delusional disorder and got this:
http://www.purgatory.net/merits/delusional.htm
Somatic type, in which the false belief focuses on a delusional physical abnormality or disorder.
One extremely rare instance of this disease is called folie à deux . It results from a close relationship with someone else who already has a delusional disorder, often under a closed environment. Both persons then share the delusion, such as the situation in the movie "Nell," where the main character is raised away from society with only her sister to associate with.
It is important to note the distinguishing factor between this disorder and paranoid schizophrenia is that in this disorder the symptoms of hallucination, incoherence, and loosened association are not present. This disorder occurs in middle-aged to older persons. However it is free from further deterioration or any type of remission. Typical is the diseased's unwillingess to participate in treatment or associate casually. It is generally believed that this delusional disorder stems not from genetic or physical means, but rather from pathological early life experiences.