The cerebral perivascular spaces are interstitial fluid-filled anatomic structures surrounding the perforating arteries. They appear as small, round or curvilinear structures on magnetic resonance (MR) imaging. Occasionally, these structures may become very large and cause mass effect. In this case, they may imitate malignant processes and are referred to as tumefactive perivascular spaces. In this study, we present a case of tumefactive perivascular space demonstrated with post-contrast time-of-flight (TOF) MR angiography. To our knowledge, there have been no previous clear demonstrations of the perforating artery in tumefactive perivascular space with contrast-enhanced TOF MR angiography. The purpose of this study was to describe advanced imaging findings in this unusual condition.