Occult Disseminated Metastatic Breast Carcinoma Presenting as Acquired Thrombotic Thrombocytopenic Purpura.

Cancer-related microangiopathic hemolytic anemia (MAHA) is a rare and life-threatening condition. We present a patient who had been treated for invasive lobular breast carcinoma in clinical remission with fever and hemolytic anemia. The peripheral blood film showed MAHA and thrombocytopenia, and a functional deficiency of ADAMTS13 activity of 23% consistent with acquired thrombotic thrombocytopenic purpura. Bone marrow aspirate and trephine biopsy confirmed metastatic carcinoma. Further evaluation revealed the involvement of multiple bone sites without recurrence of the primary tumor. The patient received a daily plasma exchange with cryosupernatant and was pulsed with corticosteroids. MAHA related to breast cancer appears to be a rare occurrence.