Autodesk AutoCAD uses both .dxf and .pat files, so it might be very well possible that users searching for dxf to pat conversion are in fact looking for a way to create patterns based out existing DXF files. PAT file in AutoCAD are used for hatch pattern which are for textures included in the AutoCAD drawing.
But of course, numerous formats do use .pat extension, so there might exist completely different conversions as well, to one of the many PAT formats. But it will always be about vector graphics and their export.