How to use an if else statement in the middle of an echo

I get Parse error: syntax error, unexpected 'if' (T_IF), expecting ',' or ';' in which is for this line if ($meta == '') . Can someone provide a bit of guidance please, so that my if else statement works in this echo? Thank-you!!!

    echo '<tr>
            <th><label for="twitter_embed">Twitter Embed</label></th>
            <td><textarea name="twitter_embed" id="twitter_embed" cols="60" rows="4">'
             if ($meta ==  '') 
              { get_option('my_option_name');
               }else{ 
                .$meta. ;
                 }'</textarea>
            <span class="description">Use to embed tweets on your post.</span></td>
            </tr>';

    echo '</table>';
}

the get_option is for wordpress . Please can someone help with this if - else statement inside an echo?