Prostate-specific antigen (PSA) is a glycoprotein derived from prostatic ductal and acinar epithelial cells. The main clinical use of PSA is as a marker of prostate tumor progression/recurrence. We present a case of a sixty-nine-year-old patient with recurrent endometrioid carcinoma of the prostate (status post-radical prostatectomy, hormonal therapy, and external beam radiation therapy) with normal serum PSA.