$re = '/^[^\r\n.]*(?<!\S)(TableA)(?!\S)[^\r\n.]*$/m';
$str = ' Test TableA
TableA AWord
TableA AWord
This.TableA
This. TableA Aword';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php