how many stages in this mast? 3? or 2?
if 3 then there are 3 cylinders, one in the center and 2 on each side
the center being the freelift cylinder and the 2 on the sides being the main lift cylinders.

as for the type of cylinder that might be in it:

if this is an older model there might be packing on the rod, that can make it difficult to pull the ram out.
But if its a newer model most are fluid displacement cylinders so there is no packing on the rod, its all in the nut on the top. The only reason to remove the rod would be to check the safety valve.

Now if it happens to be older with packing you can put the packing nut back on and then use the hydraulics to push the rod almost to the top, then take the nut off again and wiggle the rod will it comes out.
If its a newer one sometimes they are just hard to pull out if the cylinder is full of fluid. Might need to figure out a way to put a strap on it and lift it with a come-a-long or another forklift.

good luck