jabberwock ~ # equery l -p gnome-session
[ Searching for package 'gnome-session' in all categories among: ]
 * installed packages
[I--] [  ] gnome-base/gnome-session-2.16.1 (0)
 * Portage tree (/usr/portage)
jabberwock ~ # emerge -vp gnome-session

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild     U ] gnome-base/gnome-session-2.16.2 [2.16.1] USE="-branding -debug -esd -ipv6 -tcpd" 665 kB 

Total size of downloads: 665 kB
jabberwock ~ #