Occipital sinus pericranii superseding both jugular veins: description of two rare pediatric cases.

BACKGROUND AND IMPORTANCE: The extracranial venous drainage of the brain is provided mainly by the jugular veins with the variable participation of extrajugular pathways. CLINICAL PRESENTATION: Two cases of occipital sinus pericranii (SP) were observed. A 6-year-old girl presented with a progressively enlarging occipital lump; she was otherwise asymptomatic. An 8-year-old boy presented with mild nuchal headache. In the former case, neuroimaging examinations confirmed the diagnosis of SP; in the latter, SP was noticed on magnetic resonance imaging because it was neglected at physical examination. In both subjects, the radiological examination also showed bilateral occlusion of the jugular veins with ventricular dilation and herniation of cerebellar tonsils into the foramen magnum. CONCLUSION: Exceptionally, SP was noticed to represent the main venous drainage of the underlying brain, thereby compensating for the intracranial hypertension due to venous engorgement. Preservation of SP was advised, and any surgical or endovascular treatment was contraindicated.