Thrombotic microangiopathies (TMA) are defined as a triad combining mechanical hemolytic anemia, peripheral thrombocytopenia and ischemic organ damage. Mitomycin C is an alkylating agent used as chemotherapy in adenocarcinomas of the breast, lung, pancreas, rectum and anal carcinoma. Mitomycin-C-induced TMA (m-TMA) is a potentially serious complication of chemotherapy: its estimated incidence ranges from 4 to 15% and its mortality exceeds 70%, with an estimated median survival of 2 months. This can also be responsible for kidney failure, sometimes requiring hemodialysis. The time to onset of m-TMA varies from one week to 15 months after the last infusion and is believed to depend on the cumulative dose of mitomycin C. Eculizumab is a monoclonal antibody that binds to complement protein C5, blocking activation of the terminal complement pathway and formation of the membrane attack complex. This therapy has significantly changed the prognosis of patients with atypical hemolytic uremic syndrome (HUS), a disease in which complement activation plays a central role in TMA. Recently, a retrospective study suggested efficacy of eculizumab in TMA induced by gemcitabine, another chemotherapy, with normalization of platelets and LDH in 83% of patients, and partial or complete renal recovery in 67% and 17% of patients. These results provided arguments in favor of a potential benefit of complement-targeted therapies in TMA induced by certain chemotherapies. However, data on eculizumab in m-TMA remain extremely limited to date. The objective of this study is to describe the clinical, biological and histological presentation of patients with m-TMA and their evolution after treatment with or without eculizumab.