Cerebral venous thrombosis in a breast cancer patient taking tamoxifen: Report of a case

INTRODUCTION: Tamoxifen reduces breast cancer risk, but can cause thromboembolic complications. Cerebral venous thrombosis is a rare form of stroke in which blood clots occlude the dural sinus or cerebral veins. PRESENTATION OF CASE: A 46-year old female presented with a severe headache and nausea of subacute onset. She had undergone masectomy for breast cancer 20 months ago and had been taking tamoxifen. Brain CT and MRI confirmed cerebral venous infarction and venous thrombosis in the superior sagittal sinus and straight sinus. She had elevated D-dimer level, decreased levels of protein S activity and antithrombin III. Doppler ultrasound revealed concurrent deep vein thrombosis in her right leg. There was no evidence of breast cancer recurrence. With oral anticoagulation, she discharged without neurological complications. The abnormal laboratory findings of coagulopathy returned to normal after discontinuation of tamoxifen. DISCUSSION: Considering the abnormal findings in the workup of coagulopathy and no other risk factor for venous thrombosis, this thromboembolic complication can be attributed to the coagulopathy with use of tamoxifen. CONCLUSION: Clinicians should warn about the possibility of thromboembolic complications with tamoxifen.