The Collaborative International Dictionary of English v.0.48:

mutandum \mu*tan"dum\ (m[-u]*t[a^]n"d[u^]m), n.; pl. Mutanda
   (m[-u]*t[a^]n"d[.a]). [L., fr. mutare to change.]
   A thing which is to be changed; something which must be
   altered; -- used chiefly in the plural.
   [1913 Webster]