Although the association of coagulopathy and neoplastic disease is well documented, there have been few reports of patients with primary central nervous system tumors who exhibited hypercoagulable states. We report the case of a 58-year-old woman with a recurrent falcine meningioma and repeated episodes of venous thrombosis who developed warfarin-associated breast necrosis on the fifth day of coumadin therapy. Laboratory evaluation at that time demonstrated an elevated prothrombin time and normal activated partial thromboplastin time. Of the 24 cases of warfarin-associated massive necrosis of the breast described in the literature, only one other case was associated with a neoplasm, a resected craniopharyngioma.