use warnings;
use strict;
use XML::Twig;

my $xml = <<XML;
<top>
<PrvsNtfctnId><Id>92190602</Id></PrvsNtfctnId>
<CorpActnGnlInf>
<CorpActnEvtId>12345678</CorpActnEvtId>
<OffclCorpActnEvtId>USJJT</OffclCorpActnEvtId>
</CorpActnGnlInf>
</top>
XML

my $twig = XML::Twig->new(
    twig_handlers => { CorpActnEvtId => sub { print $_->text(), "\n" } }
);
$twig->parse($xml);

__END__

12345678