I have a spinal tumor at l4 and a recent abdominal x-ray shows an enhanced area at this location of spine surrounded by dark (unlike rest of spine). could this be my intradural, extramedullary tumor?

Possibly: An abdominal film does capture the L4 area. However, it's really not good for looking at soft tissues. Without knowing what type of tumor you have, i can't say for sure if what you see is your tumor. A radiologist can compare your past mris with the x-ray to know for sure.

Maybe: By your description, a purely intradural, extra medullary tumor of the spine, by definition would exclude a bone tumor. Exceptions would include a tumor that started in the place you describe and spread to involve the bone, a bone tumor that has spread into the space or a tumor that is calcified so it looks like bone in a 2d plain x-ray. A ct/mri or other imaging would likely provide the answer.