Case reports: We report two girls with a typical presentation of sinus pericranii. Both patients received total excision of the subgaleal masses with complete obliteration of the communications to the intracranial portion. However, different gross appearances, neuroimaging findings and intraoperative findings were found. It took more time and attention to control the bleeding due to the large communication between the extracranial and intracranial components in the second case.
Discussion: Sinus pericranii is composed of abnormal extracranial vascular tissues that communicate directly with intracranial dural sinuses or veins. A review of the literature showed that 13 out of 31 patients with sinus pericranii had a high-flow pattern. Detailed physical examination and imaging studies to detect dilated scalp veins and a large bony defect should remind surgeons of the presence of large venous communications. Meticulous treatment of the large communication during surgery can avoid massive bleeding.