PT - JOURNAL ARTICLE AU - Sarah Cook AU - Vahini Janarthen AU - Graham Warner TI - NEOPLASTIC VENOUS OUTFLOW OBSTRUCTION; AN UNUSUAL CAUSE OF CEREBRAL VENOUS SINUS THROMBOSIS AID - 10.1136/jnnp-2016-315106.204 DP - 2016 Dec 01 TA - Journal of Neurology, Neurosurgery & Psychiatry PG - e1--e1 VI - 87 IP - 12 4099 - http://jnnp.bmj.com/content/87/12/e1.118.short 4100 - http://jnnp.bmj.com/content/87/12/e1.118.full SO - J Neurol Neurosurg Psychiatry2016 Dec 01; 87 AB - Aim To present a case of cerebral venous sinus thrombosis (CVST) with an unusual aetiology.Case A 56 year old female was referred from her optician with bilateral papilloedema. In the preceding 2 weeks she had developed a gradual onset severe occipital headache and blurred vision. She was also under investigation for an enlarging right sided neck lump. Examination confirmed the mass deep to the sternocleidomastoid muscle, bilateral papilloedema, reduced visual acuity and right cranial nerve VI palsy. MRI demonstrated external compression of the right internal jugular vein with associated thrombosis in the internal jugular vein and transverse sinus. LP showed raised intra-cranial pressure and provided some symptomatic benefit, although significant neurology remained. A diagnosis of non-metastatic squamous cell carcinoma of the tonsil was eventually achieved and therapeutic heparin commenced whilst the patient awaited definitive treatment.Conclusion CVST is an uncommon condition with a wide range of aetiologies. Predisposing factors can co-exist in one patient: along with a neoplastic state, here, the growing tumour caused external compression of the jugular venous system, leading to venous stasis and the eventual development of a CVST.