TAFRO Syndrome and Elusive Diagnosis of Idiopathic Multicentric Castleman Disease Treated with Empiric Anti-Interleukin-6 Therapy

Abstract TAFRO syndrome is defined by the presence of thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis/renal dysfunction (R), and organomegaly (O) and can be seen with idiopathic multicentric Castleman disease (iMCD) or as an isolated process without iMCD. Although the diagnosis of iMCD in patients with TAFRO can be challenging to make, iMCD should remain high on the differential diagnosis. Similar to iMCD, the pathophysiology of TAFRO is not well understood but is thought to be related to hypercytokinemia, with interleukin (IL)-6 playing a pivotal role. Anti-IL-6 monoclonal antibody therapy is an effective treatment modality for iMCD, but to date, there is no clear guidance on treatment of TAFRO in the absence of definitive diagnosis of iMCD, leading to suboptimal management and high morbidity. We report a case of TAFRO syndrome and demonstrate benefit with the empiric use of anti-IL-6 antibody therapy in the context of delayed diagnosis of iMCD.