Objectives Dural venous sinus cysts are rarely reported¹ and of radiological importance given the potential for misdiagnosis as cerebral venous sinus thrombosis. They are predominately asymptomatic, and are usually an incidental finding on cranial imaging.^2,3 Potential radiological misdiagnoses include venous sinus thrombosis, dural sinus adipose tissue, arachnoid granulations, and aeroceles.^2,3

Case A 55 years old male presented with a ten-day history of severe headache, intermittent right monocular scotoma and intermittent right hemisensory disturbance. Relevant background history included diabetes mellitus, hypercholesterolemia, ischaemic heart disease with percutaneous intervention (PCI), and migraines (self-medicated with triptans despite vascular disease) characterised by left hemi-cranial headache, transient right eye positive visual phenomenon, nausea, vomiting, photophobia and phonophobia. Clinical examination revealed a right monocular scotoma and otherwise was unremarkable.

Results Non-contrast CT brain scan revealed a long, well-defined hypodense filling defect in the right transverse sinus suspicious for dural venous thrombus. Classic CT and MRI features that define and differentiate dural venous sinus cyst and venous sinus thrombosis are clearly represented and discussed. Discerning characteristics described included lesion density and morphology, associated brain parenchymal changes, differences in T1 imaging, T2 imaging, susceptibility weighted imaging, CT and MRI contrast imaging, and diffusion weighted imaging. Final diagnoses were migraine, right dural venous sinus cyst and left occipital lobe stroke (contralateral to the dural venous sinus cyst) in the setting of multiple vascular risk factors, migraine, and triptan use. The patient was initially treated with therapeutic anticoagulation however this was ceased after the final diagnosis was revised to dural venous sinus cyst.

Conclusions Radiological differentiation between venous sinus thrombosis and dural venous sinus cyst is clinically important to avoid unnecessary anticoagulation and associated risks. Final management included propranolol for migraine prophylaxis; aspirin for acute migraine; aspirin for stroke prevention; vascular risk factor management; and cessation of triptans.