PURPOSE: To report a case of partial transverse venous sinus obstruction causing a syndrome resembling pseudotumor cerebri. METHOD: Case report. A 61-year-old man developed decreased vision, bilateral papilledema, and a highly increased cerebrospinal fluid opening pressure. Brain magnetic resonance imaging (MRI) disclosed a small, extra-axial mass near the torcula, which was dismissed as an incidental meningioma because cerebral angiography showed sinus patency. RESULTS: The patient’s vision worsened. Biopsy of the enlarging mass disclosed metastatic prostate cancer. After radiation therapy, the mass shrank, magnetic resonance angiography disclosed reopening of the transverse sinuses, and papilledema resolved, but visual fields remained severely compromised. CONCLUSION: Partial blockage of the dural venous sinus by a small mass near the torcula can cause a sufficient increase in intracranial pressure to produce vision-threatening papilledema.