According to the Mayo Clinic, a person with Narcissistic personality disorder exhibits the following characteristics:
inflated sense of importance and superiority
have little regard for others
exaggerate their achievements or talents
expect constant praise and admiration
are jealous of others and feel others are jealous of them
have trouble keeping healthy relationships
pretend to be tough but are actually easily hurt
comes across as conceited, boastful or pretentious
feels a sense of entitlement
if not receiving the 'special treatment' will become very impatient or angry
insist of having the best of everything - best car, social circles, etc...
have trouble handling anything that may be perceived as criticism
http://www.mayoclinic.com/health/narcissistic-personality-disorder/DS00652
It's amazing because this seems to be an exact match of at least one boxer that we all know about.
When to see a doctor
When you have narcissistic personality disorder, you may not want to think that anything could be wrong — doing so wouldn't fit with your self-image of power and perfection. But by definition, narcissistic personality disorder causes problems in many areas of your life, such as relationships, work, school or your financial affairs. You may be generally unhappy and confused by a mix of seemingly contradictory emotions. Others may not enjoy being around you, and you may find your relationships unfulfilling.