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Neuroradiology Case of the Week

Case 509

August 2010

Richard Gong, MD

Clinical Presentation: Patient initially presented at 2 months of age for assessment of a cutaneous vascular malformation, clinically diagnosed as sinus pericranii. Imaging was performed to evaluate the intracranial extent and for calcifications.

Imaging Findings: Axial and coronal post-contrast SPGR images demonstrate cutaneous vessels at the forehead with intracranial extension into the superior sagittal sinus with thickened, enhancing lesion at the anterior falx. Sagittal T1 post-contrast image demonstrates the intracranial component of the lesion in the sagittal view. Noncontrast CT of the head shows calcification in the anterior interhemispheric fissure within the known sinus pericranii.

Diagnosis: Sinus pericranii

Discussion: Sinus pericranii is a rare vascular entity characterized by the anomalous communication of the extracranial venous system with the intracranial dural sinuses. Although the etiology is unknown, congenital, spontaneous and traumatic origins have been proposed. Most cases are asymptomatic. When symptoms do occur they include mild headache, vertigo and nausea. The majority of cases become clinically apparent as nonpulsatile masses in the midline frontal region. Off midline sinus pericranii are less common. The anomalous vessels enlarged with crying or Valsalva and shrink with head elevation and compression.
     The age of presentation vary from birth up to the third decade in one series. The natural history is favorable with no evolution in size after puberty and a low risk of spontaneous or traumatic bleeding. There are reports of spontaneous involution or partial thrombosis.
     Contrast enhanced MRI and MRA/MRV may be considered the diagnostic imaging modalities of choice. The presence of sinus pericranii and its drainage into the dural sinuses can be readily demonstrated. Digital subtraction angiogram is usually not needed for the initial diagnosis, but could be useful during treatment to document the flow dynamics. Skull radiographs may show osseous defects, cortical thinning or focal bone lesions. Color doppler ultrasound may be particularly useful in younger patients, demonstrating blood flow from the dural sinus through the calvarial defect into the extracranial system.
     Although several authors have divergent opinions, treatment is usually conservative and sought most commonly for cosmesis. Available treatments include surgical ligature and endovascular embolization

References:

1. Rozen WM, Joseph S, Lo PA. Spontaneous involution of two sinus pericranii – a unique case and review of the literature. J Clin Neurosci. 2008 Jul; 15(7): 833-5 PMID: 18342516 [PubMed]
2. Gandolfo C, Krings T, Alvarez H, et al. Sinus pericranii: diagnostic and therapeutic considerations in 15 patients. Neuroradiology 2007 Jun;49(6): 505-514. PMID: 17285338 [PubMed]
3. Carpenter JS, Rosen CL, Bailes JE, Gailloud P. Sinus pericranii: clinical and imaging findings in two cases of spontaneous partial thrombosis. AJNR Am J Neuroradiol 2004 Jan;25(1): 121-125. PMID: 14729540 [PubMed]