  We show that the retrograde perihelion precession of Saturn \Delta\dot\varpi,
recently estimated by different teams of astronomers by processing ranging data
from the Cassini spacecraft and amounting to some milliarcseconds per century,
can be explained in terms of a localized, distant body X, not yet directly
discovered. From the determination of its tidal parameter K = GM_X/r_X^3 as a
function of its ecliptic longitude \lambda_X and latitude \beta_X, we calculate
the distance at which X may exist for different values of its mass, ranging
from the size of Mars to that of the Sun. The minimum distance would occur for
X located perpendicularly to the ecliptic, while the maximum distance is for X
lying in the ecliptic. We find for rock-ice planets of the size of Mars and the
Earth that they would be at about 80-150 au, respectively, while a
Jupiter-sized gaseous giant would be at approximately 1 kau. A typical brown
dwarf would be located at about 4 kau, while an object with the mass of the Sun
would be at approximately 10 kau, so that it could not be Nemesis for which a
solar mass and a heliocentric distance of about 88 kau are predicted. If X was
directed towards a specific direction, i.e. that of the Galactic Center, it
would mimick the action of a recently proposed form of the External Field
Effect (EFE) in the framework of the MOdified Newtonian Dynamics (MOND).
