Administration Structure to list menu items fails to display
If you want to modify only breadcrumb, then you can use one of below module.

custom breadcrumbs:


  Allows administrators to set up parametrized breadcrumb trails for any
  node type, Views, Panels, Taxonomy vocabularies and terms, paths . This allows node types to have "Home > User
  Blog > 2005 > January" style breadcrumbs on the node view page
  itself, synchronizing cleanly with custom views or pathauto aliases.
  Breadcrumb visibility can be customized via a php snippet.


path breadcrumbs


  Path Breadcrumbs module helps you to create breadcrumbs for any page
  with any selection rules and load any entity from the URL!