Tamoxifen A new risk factor for cerebral sinus thrombosis

Cerebral sinus thrombosis (CST) can cause cerebral venous infarcts, frequently hemorrhagic. CST has many etiologies including otitis media, trauma, pregnancy, hypercoagulable states, and cancer. Systemic thrombosis is well recognized in cancer patients because of associated hypercoagulability, metastatic spread, and direct tumor infiltration and as a complication of chemotherapy.1 Tamoxifen, a selective estrogen-receptor modulator, is the most common hormonal therapy in the treatment and prophylaxis of breast cancer. One of its known side effects is systemic thromboembolic events.2 Recently, two reports have related tamoxifen to CST in absence of other risk factors.3,4⇓ To confirm this association, we report two patients receiving tamoxifen treatment who developed CST. ### Case 1. A 46-year-old woman presented with a 7-day history of intense right hemicranial headache, right ear tinnitus, and nausea. Past medical history included breast cancer 5 years previously treated with quadrantectomy, axillary dissection, and local radiotherapy. A local recurrence was detected 3 years later. Radical mastectomy was performed, and treatment with tamoxifen 20 mg/day was initiated. At the time of admission, neurologic and funduscopic …