xanthoma vs skin disease

xanthoma and skin disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
xanthoma	Yes	No	No	No
skin disease	Yes	No	No	No

As nouns, skin disease is a hypernym of xanthoma; that is, skin disease is a word with a broader meaning than xanthoma:

xanthoma: a skin problem marked by the development (on the eyelids and neck and back) of irregular yellow nodules; sometimes attributable to disturbances of cholesterol metabolism
skin disease: a disease affecting the skin

Other hypernyms of xanthoma include disease of the skin, skin disorder.

xanthoma (noun)	skin disease (noun)
a skin problem marked by the development (on the eyelids and neck and back) of irregular yellow nodules; sometimes attributable to disturbances of cholesterol metabolism	a disease affecting the skin