Part of a swarm of objects orbiting the Sun beyond Neptune, following an eccentric and often highly inclined orbit of the type first detected in Pluto (and thus objects of this kind are known as plutinos). These bodies have orbits that are resonant with that of Neptune: for every two orbits of the Sun made by Neptune, each plutino will complete three (with each of these long orbits taking just under 250 years to complete).
2003 AZ84 is an example of such a body, and its orbit can carry it out to a distance of 46.6 AU from the Sun, but it is currently on the long inward leg of its orbital path, and will reach its perihelion in the year 2107. At this point - its closest approach to the Sun - it will still be some 32.6 AU distant from the heart of the Solar System, farther from the Sun than Neptune.
Details of the physical structure of 2003 AZ84 are not well established, but it appears to have a diameter of 700 km or more, and thus likely qualifies as a dwarf planet, though it has not yet been officially recognised as such. There are indications that 2003 AZ84 possesses a small orbiting moon, but this observation has still awaiting definitive confirmation.