Sinus pericranii - the final diagnosis was based on the clinical, radiological and histopathological findings.
The postoperative course was uneventful. There was no recurrence after 3 years of follow-up.
Sinus pericranii is a rare vascular abnormality, which was first described by Hecker in 1845 as a "varix spurious circumscriptus venae diploicae frontalis" (1). Stromeyer changed the name in 1995 to "Sinus pericranii" describing the lesion as "a blood bag on the skull which stands in connection with the veins of the diploe and through theses with the sinuses of the brain, whereby an imperfect formation of the outer osseous lamella is easily palpable" (1).
Prior to June 2014, there were more than 200 cases reported in published literature. There is a wide spectrum for age of onset, ranging from 7 weeks of birth to 64 years, with a significant incidence peak in children. It has been suggested than Sinus pericranii occurs in young patient when the origin is congenital or spontaneous and arises adults for cases of traumatic origin (1). It occurs equally in both sexes. With regards to the onset site, most cases involved frontal lobe near the superior sagittal sinus, followed by the parietal lobe, the occipital lobe and only 3 cases occurred in the temporal lobe (1). Some cases presented parieto-occipital lesion or fronto-parietal or occipito-temporal. It presented as a rarely pulsatile mass of the skull. Patients are usually asymptomatic and local pain, nausea, vertigo, headaches are rare. In traumatic cases, the delay between the trauma and the occurrence of Sinus pericranii is highly variable, ranging from few months to several years as in our case. The traumatic event is often minor.
MRI with contrast is the best tool to diagnose Sinus pericranii, showing the connection of the vascular mass to an intracranial dural venous sinus (1). CT scan shows associated bone defect and the enhancement of the mass with intravenous contrast (2). Differential diagnoses are clinical and radiological. The main differential diagnosis is post-traumatic arteriovenous. It is a pulsatile mass with thrill. Cavernous hemangiomas may clinically look like Sinus pericranii but they are localized in the subcutaneous tissue and do not adhere to the skull and they do not communicate with intracranial veins (2). In children, clinical differential diagnoses include meningoceles and meningoencephaloceles but radiologically they do not contain vascular structures (2).
Other lesions and malformations have been reported associated with Sinus pericranii such as scaphocephaly, systemic angiomas, mutlisutural synostosis, Crouzon and oxycephaly (1, 3, 4, 5, 6).
Histologically, the lesion is compound of large, abnormal muscular vein of irregular thickness associated with proliferation of small vessels without own muscular layer (1). The histogenesis of Sinus pericranii has been unclear and debated. In one hand, some authors proposed that it may result from trauma (1). Indeed, several cases, as in our observation have reported a cranial injury before the apparition of Sinus pericranii. In another hand, other authors have proposed a congenital origin. Indeed, a lot of documented cases have been described in children. Moreover, in several cases, Sinus pericranii is associated with other vascular malformation suggesting a congenital predisposition to vascular disorders included in syndromes as it was defined in Sturge-Weber syndrome. Macit et al. have observed association of Sinus pericranii with cortical dysplasia, comforting the congenital hypothesis (7). This lesion may be result to an incomplete fusion of sutures (craniosynostosis) or a dural sinus thrombosis with development of unusually large emissary veins between intracranial veinous sinus and the cranial vault (3). Considered by some authors as a true angioma, Sinus pericranii can be associated with other vascular malformations (7).
When Sinus pericranii is symptomatic or if it induces cosmetic deformities, it has been successfully treated by total resection without exceptional old cases of recurrences in the literature. Treatment by surgical excision or endovascular procedure has been advised to prevent rare complications such as hemorrhage, thrombosis or embolism (2). There also have been described spontaneous involutions (8),(9). The main risk of the surgery is profuse bleeding (2). Some authors have shown a benefit in endovascular transvenous embolization in treatment of Sinus pericranii (10).
Contributed by Arnault Tauziède-Espariat, Alain Czorny, MD, PhD, Alain Cangemi, MD, Gabriel Viennet, MD