A combination of magnetic resonance (MR) methods (T2-weighted MRI, proton MR spectroscopy, and dynamic contrast enhancement) gives the highest sensitivity and specificity for identification of prostate cancer by MRI. The prostate MR findings of a patient with a congenital cystic disease of seminal vesicle are presented. To our knowledge, this is the only case described in the literature. The MR examination resulted in a false-positive indication of prostate cancer.