How to associate markdown files with a web browser?

Out of GUI-based software like ReText or Formiko, and using just a _command-line tool_ like pandoc, is it possible to open markdown files (MIME type association) as an HTML file in a web browser, without any browser-addon too? Notice that the original markdown file may include links to images or any kind of resources. Therefore, this process should be on-fly (stdout?), without saving the output HTML file to somewhere else like /tmp/ directory. And how can such a command be included in a .desktop file?