Sinus pericranii: diagnostic and therapeutic considerations in 15 patients.

INTRODUCTION: Sinus pericranii (SP) is a rare, usually asymptomatic condition characterized by a large communication between the intra- and the extracranial venous drainage pathways in which blood may circulate bidirectionally through dilated veins of the skull. We describe our diagnostic and therapeutic experience with SP, with a special focus on the vascular analysis of digital subtraction angiography (DSA). METHODS: DSA images of 15 patients were evaluated with regard to the delay in opacification of the scalp vessels, the absence or distortion of the superficial cortical veins in the vicinity of the SP, the drainage patterns of the superior sagittal sinus, and the degree of maturation of the venous outlets of the brain. SP were classified either as "dominant", if the main stream of contrast flow used the SP to drain the brain bypassing usual venous outlets, or as "accessory", if only a small part of the venous outflow occurred through the extradiploic vessels. RESULTS: All patients presented with a nonpulsatile, soft-tissue mass. The lesion was on the midline in 14 of 15 patients, frontal in 12 patients, and parietal in 2 patients. In 13 patients, associated intracranial venous anomalies were present, eight of which were developmental venous anomalies. Seven patients had a dominant SP, and eight an accessory SP. CONCLUSION: SP can be considered the cutaneous sign of an underlying venous anomaly. If treatment is contemplated, analysis of the drainage pattern of the SP has to be performed. Treatment should be avoided in dominant SP or if its accessory role constitutes the only collateral pathway of an underlying venous anomaly.