Source : Webster's Revised Unabridged Dictionary (1913)

Xanthoma \Xan*tho"ma\, n. [NL. See {Xantho-}, and {-oma}.]
   (Med.)
   A skin disease marked by the development or irregular
   yellowish patches upon the skin, especially upon the eyelids;
   -- called also {xanthelasma}.

Source : WordNet®

xanthoma
     n : 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