Can pituitary tumors affect my memory?

Not usually: Unless it affects the thyroid or adrenal axis.

Yes but not often: If the tumor is secreting a hormone, that might directly or indirectly affect your mood and cause memory problems. The memory centers of the brain are not near the pituitary gland and therefore even large pituitary glands are not likely to affect memory just by enlarging. Such a tumor would need to be massive and would cause other problems before affecting memory. Radiation therapy can rarely.