Can paralyzing effects of a stroke due to a pituitary tumor be reversed by removal of the tumor?

Very unlikely: First, unless it is extremely large, a pituitary tumor will rarely, if ever, be a cause of a stroke. It is more likely that after a stroke that was caused by a different problem, a MRI revealed an unsuspected pituitary tumor. Rehabilitation is much more likely to help a stroke victim that treatment of the tumor.

Maybe: Pituitary tumors confined to the sella (home of the pituitary gland) won't cause paralysis absent major hormonal disruption. Paralysis will occur only if the tumor extends beyond the sella, compressing other brain structures or blood supply. In the modern era of mri, it is difficult to conceive of a tumor being undiagnosed until such extreme symptoms without massive, rapid growth.