use warnings;
use strict;
use XML::LibXML;

my $dom = XML::LibXML->load_xml(IO=>\*DATA);
print "### Before:\n", $dom->toString;
for my $el ($dom->findnodes('/foo/bar/quz')) {
	$el->textContent eq 'baz'
		and $el->parentNode->unbindNode;
}
print "### After:\n", $dom->toString;

__DATA__
<foo>
  <bar>
    <quz>baz</quz>
  </bar>
  <x/>
  <bar>
    <quz>abc</quz>
	<y/>
  </bar>
</foo>