[Thrombotic microangiopathy developing subsequent to tocilizumab therapy in a patient with TAFRO syndrome]

We report a case of a 60-year-old male who presented with fever and anasarca as well as hepatosplenomegaly, general lymphadenopathy, and disseminated intravascular coagulation (DIC), and was, therefore, admitted to our hospital. In addition, the patient suffered from respiratory failure and renal dysfunction and had pleural effusion and ascites. The pathological diagnosis from lymph node biopsy suggested multicentric Castleman's disease of the plasma cell type; however, the presence of high IL-6 levels, myelofibrosis, thrombocytopenia, anasarca, renal dysfunction, and hepatosplenomegaly led to a definitive diagnosis of TAFRO syndrome. Tocilizumab was administered on day 15 of disease diagnosis, resulting in the improvement in DIC but not other symptoms. As schizocytes were detected in the peripheral blood, he also experienced disturbance of consciousness and thrombotic microangiopathy (TMA) was considered. Following plasma exchange (PE) and continuous hemodiafiltration (CHDF), his symptoms temporarily improved. However, his condition worsened again, and he eventually died on day 33. Pathological autopsy revealed that although the lymph nodes were not enlarged, he had organomegaly, gastrointestinal and omental hemorrhage, and acute necrotizing pancreatitis. Since TMA developed after the administration of tocilizumab, the possibility of drug-induced secondary TMA cannot be ruled out.