Rare anatomical variation in transverse sinuses (duplication on right, hypoplasia of left) falsely mimicking transverse sinus thrombosis probably due to resultant slow flow.

To cite: Monigari N, Deshpande A, Vedartham V, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013202937 DESCRIPTION We report the case of a 30-year-old, 2 weeks postpartum female, with a history of right temporal headache, intermittent, holocranial in nature, moderate intensity with associated nausea and vomiting when headache was severe. Symptoms were worse since the past 10 days. Neurological examination including funduscopy was unremarkable. A probable diagnosis of transformed migraine without aura was made; however, in view of the new onset headache during postpartum status MRI of the brain was performed to rule out the possibility of cortical venous thrombosis. MRI of the brain showed the absence of flow void in the right transverse sinuses (figure 1), MR venogram showed normal filling of the entire venous system. However, there was a presence of bifid transverse sinus on the right side, hypoplastic left sinus with normal flow-related enhancement on the left side (figures 2–4). This was a rare incidental finding. Hypoplasia of the left transverse sinus is a wellknown anatomical variation. Two previous studies showed the incidence of left hypoplastic sinus to be 24% and 31% of normal asymptomatic population on MR venography. Duplication of right transverse sinus is seen in our patient which to the best of our knowledge has not been reported previously.