Sinus pericranii is a rare vascular anomaly, and most cases occur in children and develop at the midline. In previous reports of sinus pericranii, T2 hyperintensity lesion has not been regarded as a common sequela. We report an extremely rare case of orbital sinus pericranii with associated T2 hyperintensity lesion. A 50-year-old man was admitted to our hospital with a history of right upper eyelid swelling that had been present for several years. Computed tomography, magnetic resonance imaging, and digital subtraction angiography demonstrated a connection between the lesion and normal cerebral venous system. Thus, we diagnosed the lesion as a sinus pericranii despite its atypical features. We elected to observe the patient, and the lesion had remained the same size without any adverse events, such as hemorrhage, occurring throughout the 5-year follow-up. An atypical sinus pericranii should be considered in patients with a soft compressible swelling on the head, even if the lesion is located off the midline.