Although incidental pituitary findings on 18F-FDG PET are uncommon, there are several reports published in the literature. It is believed that this is the first reporting of incidental pituitary disease found on O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) PET imaging. The case provides valuable insight into pathogenesis, diagnostic tools, and related pathology. The power of 18F-FET in differentiating cerebral metastases and recurrence in patients who had previous surgical and radiation therapy is highlighted, and the incremental benefits over MR imaging and 18F-FDG PET are outlined. The case represents an uncommon finding on MR imaging and 18F-FDG PET and a rare finding on 18F-FET PET.