How to theme content edit page
Ok, I find an answer. In my case the proper theme suggestion was html--node--edit.tpl.php I used theme debug mode to find it. 

Also, to make page--node--edit.tpl.php works I need to delete my page--contenttype.tpl.php file. To customize my content type page I just used simple check in page.tpl.php if($node-&gt;type == 'book'):

&lt;!-- THEME DEBUG --&gt;
&lt;!-- CALL: theme('html') --&gt;
&lt;!-- FILE NAME SUGGESTIONS:
   * html--node--edit.tpl.php
   * html--node--209.tpl.php
   * html--node--%.tpl.php
   * html--node.tpl.php
   x html.tpl.php
--&gt;