Something like this?

#! perl -slw
use strict;
$|=1;

my $tree = {
    top => {
        inetUser => {},
        person => {
            organizationalPerson => {
                managedPerson => {
                    personnel => {}, 
                }, 
            }, 
         },
        application => {
            managedApplication => {}, 
        }, 
    },
 };
 
sub explore;
sub explore {
    my( $tree, $leaf ) = @_;
    for my $node ( keys %$tree ){
        return $node if $node eq $leaf;
        next unless keys %{ $tree->{ $node } };
        my @found = explore $tree->{ $node }, $leaf;
        return ( $node, @found ) if @found;
    }
    return;
}

printf "Looking for %-20s: %s\n", $_, join ' -> ', explore $tree, $_ 
    for qw[ fred inetUser managedApplication personnel ];
    
__END__
P:\test>test
Looking for fred                :
Looking for inetUser            : top -> inetUser
Looking for managedApplication  : top -> application -> managedApplica
+tion
Looking for personnel           : 
    top -> person -> organizationalPerson -> managedPerson -> personne
+l
[download]