Characteristics of Recurrent Congenital Sinus Pericranii: Case Report and Review of the Literature.

Sinus pericranii (SP) involves transosseous vessels that connect the intra- and extracranial venous systems. Accessory-type SP can be cured by surgical or endovascular treatment. Reports of recurrence are, however, rare.A boy presented with a soft-tissue mass on the left parietal region of the head. Computed tomography and magnetic resonance imaging revealed the congenital SP with several small transosseous vessels surrounded by an area of thin bone. At the initial surgery, the vascular mass was completely excised by coagulating and cutting the -transosseous vessels. The skull defect was filled with bone wax. Two years later, SP recurred at the same site. At the second surgery, the skull defect and surrounding area were sealed with acrylic resin. The boy has been followed up for 6 years without recurrence.Potential risk factors for recurrence proposed in the existing literature include an unusually large number of emissary veins, rich circulation between intra- and extracranial venous systems, large bone defects, raised intracranial pressure, and association of other developmental venous anomalies. Our case demonstrates that thin skull bone around the original lesion can be another risk factor for recurrence.Removing all abnormal vessels and sealing the skull defect as well as the surrounding thin bone area are important to prevent recurrence of congenital SP.