The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Xanthelasma \Xan`the*las"ma\, n. [NL.; Gr. xanqo`s yellow +
   'e`lasma a metal plate.] (Med.)
   See Xanthoma.
   [1913 Webster]

WordNet (r) 3.0 (2006):

xanthelasma
    n 1: xanthoma of the eyelids; occurs chiefly in the elderly