Is there such a thing as anorexic dwarf?

No, there's no such thing as an anorexic dwarf. I'm not aware of any evidence to support this claim.

Anorexia nervosa is an eating disorder that affects the way a person thinks about food and their body weight. It can lead to severe weight loss and a range of other health problems. Dwarfs are people with short stature, typically due to a genetic condition. There is no connection between the two.