Far IR (90 microns) ISO Maps of four Seyfert galaxies are presented. We find that the Far Infrared emission is extended in all cases out to radii comparable to optical radii. The spatial extension of the Far IR maps is also comparable to the optical extension of these objects, an indication of the extended nature of their far-IR emission. The 90 micron intensity profiles of these galaxies shows that there is a disc component noticeable in the far IR ISO maps. To reach these conclusions an ISO PSF has been modeled that compares satisfactorily with an actual IRAS point source observed by ISO under the same instrumental conditions. Several tests of the PIA mapping algorithm are presented to explain the algorithm selected by us and to dispel doubts that still may exists about the PHT32 maps.