A 40-year old male is admitted with complaints of abdominal pain and headache. General physical examination revealed six scars on the abdomen from previous surgeries. He seems to maintain a sick role and seeks attention from the nurses. He demands multiple diagnostic tests including a liver biopsy. The treating team failed to diagnose any major physical illness in the patient. His mental status examination did not reveal any major psychopathology. One of the treating staff recognized him to have appeared in several other hospital with abdominal pain and some other vague complaints. He is most likely suffering from: