Short answer, no, this is not possible. The column depth of an atmosphere is based on the gravity of the planet and the total mass of the atmosphere. A gas will expand to fill its container (that's the prime definition of a gas), and in this case the container is the extent that gravity can hold it to the planet.
However, all is not lost if you're willing to play with your planet's geology a little.
If you assume that above 60 degrees latitude there is a very large mountain range that increases in altitude until it gets to the poles, it becomes possible to thin your atmosphere out.
This somewhat stretches credibility from a plate tectonics standpoint, but it shouldn't be impossible. What you need to do is have two large plates at either end of the planet, then along the equator have rifts that spread outward. This is somewhat opposite from Earth's plate tectonics, where the rifts and subduction zones generally travel along north-south longitudes, but there's no real reason that you couldn't turn everything 90 degrees and have spreading along latitudes.
On Earth rifts and subduction zones are generally in the oceans, but not always. Iceland is a prime example of where rifts come up onto land, but subduction zones are almost invariably under the ocean (they push down the crust, and eventually it falls below sea level). However, the Himalayan mountains are very similar to a subduction zone, and it's no coincidence that the Earth's tallest mountains are in the Himalayas.
So your planet would probably have the following characteristics:
A large equatorial sea containing a rift zone around the equator of the planet. This pushes new plate material north and south, where it collides with the polar plates at around 60 degrees latitude. Because the collisions happen along the entire circumference of your planet, they push inward on the plate, forcing massive mountains up at the poles. These mountains are extremely tall, perhaps 1.5 times as tall as Everest, but much wider, covering nearly the entire polar continents, so, like Olympus Mons on Mars, you can't really tell you're on top of a mountain at the poles. Because they rise so much in altitude, the pressure drops dramatically. In fact, at 10% pressure it is nearing the Armstrong limit, where water boils at the temperature of the human body (in reality on Earth this limit is around 60,000 feet, so a mountain twice as tall as Everest would be well above it).
Because of the massive subduction zones surrounding your polar continents, the coast lines have a reputation for producing massive tsunamis every few hundred years. Most people avoid living by the seas because of this. Those that do build on high ground and have learned to construct dwellings that can either withstand large earthquakes or be easily rebuilt after them.
The equatorial seas have no real land masses to obstruct winds, so extremely high winds are able to form. Maybe the areas below 30 degrees latitude are known as "The Banshee's Tempest" due to the strong storms that are almost constantly forming. Below 10 degrees latitude however, is the "Central Oasis Belt" where strong storms are unable to form due to Hadley cells and the intertropical convergence zone suppressing them. Since this area is also near the spreading rifts, small island chains would likely form when the rift mountains get large enough to peak above sea level, perhaps resulting in many small island nations around the belt of your planet. Because the islands are bordered to the north and south by the Banshee's Tempests, the island nations are mostly isolated from the rest of the world.