Microangiopathic hemolytic anemia associated with metastatic breast cancer: case report and literature review

INTRODUCTION: Microangiopathic hemolytic anemia (MAHA) is a mechanical hemolytic anemia characterized by the emergence of fragmented red cells in peripheral blood. Here, we report a case of breast cancer associated with cancer-related (CR)-MAHA along with a literature review. CASE DESCRIPTION: The patient was a 54-year-old woman who made an emergency visit to our hospital because of low back pain, shoulder pain, visual impairment, and anemia. She was diagnosed with stage IV, ER-positive, PgR-positive, HER2-negative left breast cancer (invasive lobular carcinoma), with left axillary adenopathy, metastasis to the soft tissue of the orbital region, multiple bone metastases, pleural dissemination, and metastasis to the stomach and para-aortic lymph nodes. Chemotherapy was initiated successfully; tumor marker levels normalized and the visceral metastases almost disappeared. Hormone therapy was administered for maintenance. Two and a half years later, rapid elevation in tumor marker levels and severe anemia were noted, and fragmented red cells and poikilocytes emerged in the peripheral blood. Positron emission tomography–computed tomography and bone scintigraphy revealed multiple bone metastases, but no evidence of visceral metastasis. CR-MAHA associated with multiple bone metastases was diagnosed, and Paclitaxel chemotherapy was initiated with frequent blood transfusions. Her anemia gradually improved, with a decrease in tumor marker levels and the number of blood transfusions. Three months later, tumor marker levels increased again. Because the anemia was also exacerbated, chemotherapy was changed to eribulin. Tumor marker levels temporally decreased, and the anemia tended to improve, but 3 months later, the levels were elevated again and the anemia was exacerbated. A switch to another regimen was planned, but best supportive care was chosen instead because of rapid deterioration of liver function. The patient died a month later. DISCUSSION AND EVALUATION: CR-MAHA is thought to have a different pathologic mechanism from TTP or HUS. Although CR-MAHA is a clinical condition associated with a very poor prognosis, we consider it controllable for long period by rapid introduction of chemotherapy in many cases. CONCLUSIONS: CR-MAHA is a nearly oncologic emergency that medical oncologists need to be able to recognize even though it rarely occurs in breast cancer.