Dynamic page content
I think you're just looking for a standard page callback for your menu item. To extend the example from the hook_menu() docs slightly:

function mymodule_menu() {
  $items['abc/def'] = array(
    'page callback' =&gt; 'mymodule_abc_view',
  );
  return $items;
}

function mymodule_abc_view() {
  $text_content = 'Text to print to the page.';

  // You could just return the string itself here, that will also work fine,
  // but it's 'best-practice' to return a render array so other parts of the system
  // can alter the content if they so desire.
  return array(
    '#markup' =&gt; $text_content
  );
}


Remember to clear Drupal's caches after making the changes to hook_menu(), or they won't be picked up.