Sinus pericranii is a rare vascular anomaly involving an abnormal communication between the extracranial and intracranial circulations. A 33-year-old woman presented with a soft tissue mass at the left frontal region. It was associated with head trauma when she was 12-year-old. The mass had gradually grown and become painful for 20 years. She underwent surgical resection of the mass successfully. This report discusses traumatic sinus pericranii.