Thrombosis of acute superior mesenteric artery in a patient with breast cancer receiving toremifene therapy: a case report and literature review.

It is widely recognized that cancer itself is related to increased risk of thromembolism. Venous thromboembolism is relatively common in breast cancer patients, but arterial thrombosis, especially acute superior mesenteric artery thrombosis (SMAT) associated with chemotherapy or endocrinotherapy, rarely occurs in breast cancer patients. There were few reports about acute SMAT in cancer patients who underwent chemotherapy, but no reports of acute SMAT caused by endocrine-therapy. We reported a 54-year-old patient with acute SMAT during toremifene treatment after breast cancer surgery. She underwent 4 cycles chemotherapy of TC regimen, then accepted toremifen endocrinotherapy because of positive estrogen receptor. She suffered from acute SMAT after 2 months toremifen treatment. Therefore, we consider that this case of acute SMAT may be a rare adverse event of toremifen. In view of the high risk and rarity of acute SMAT caused by toremifene, we suggest that except for venous thrombosis, arterial thrombosis in special position (ATSP) should be kept in mind during use of toremifene. Once a thrombotic event occurs, toremifene should be stopped immediately.