Apply the WordPress content filters to a string of HTML from a custom field within the WordPress loop. The enables oEmbed, wp_texturize, etc.

WordPress Apply Content Filter

<?php $my_custom_content = get_post_meta( $post->ID, 'my_custom_content_meta_key', true ); ?>
  	
<?php if ( '' != $my_custom_content ) : ?>
		<?php echo apply_filters( 'the_content', html_entity_decode( $my_custom_content ) ) ?>
<?php endif; ?>

it work!