TITLE: Finite outer automorphism groups
QUESTION [11 upvotes]: It is a theorem of Gopal Prasad (which I hope I am not misquoting...) that lattices in higher rank linear semi-simple Lie groups have finite outer automorphism groups. Is there some other reasonable class of groups with this finiteness property?

REPLY [4 votes]: The theorem Igor Belegradek mentions is a more general form of the theorem (due collectively to Bestvina, Feighn, Paulin, and Rips) that a one-ended hyperbolic group has infinite outer automorphism group only if it splits over a two-ended subgroup. See 
M. Bestvina, M. Feighn, 
Stable actions of groups on real trees. 
Invent. Math. 121 (1995), no. 2, 287-321.