Don't think you can, but don't have 2014.
You could convert the .pat to a compatible image file like jpeg or png or tiff if it's vector. then create a new material and use the image?
Are you talking of .pat photoshop files?
If you mean .pat autodesk hatch file (which reading your post again I think you do mean sorry) then you can do it a couple of different ways.
You can find and open the acad.pat in notepad (or acadiso.pat if you're metric like me) and the custom one and append the acad.pat (they are text files).
or
add the file path in the support file locations.
Should appear in the custom tab through the hatch dialog box.