A Case of Thrombocytopenia, Anasarca, Fever, Reticulin Fibrosis, and Organomegaly (TAFRO) Syndrome Initially Presenting as Systemic Lupus Erythematosus: Diagnostic Reconsideration Based on Long-Term Clinical Course

We report the case of an 80-year-old man who was initially diagnosed with systemic lupus erythematosus (SLE) based on thrombocytopenia, serositis, hypocomplementemia, and autoantibody positivity and achieved remission following glucocorticoid therapy.At that time, bone marrow examination showed no reticulin fibrosis.Four and a half years after discharge, he developed recurrent thrombocytopenia, anasarca, organomegaly, and renal dysfunction, all of which were refractory to conventional immunosuppressive therapy.Reevaluation revealed disappearance of autoantibodies, normalization of C3 and C4 levels according to the institutional reference ranges, and newly detected mild bone marrow reticulin fibrosis (MF-1), supporting a clinical diagnosis of thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly (TAFRO) syndrome.Clinical improvement followed the introduction of tocilizumab as part of treatment that also included glucocorticoids, intravenous immunoglobulin, and romiplostim.This case highlights the diagnostic challenge in distinguishing SLE from TAFRO syndrome in patients with overlapping clinical features.The longitudinal clinical course, including changes in serological findings and comparison of bone marrow pathology at two admissions, illustrates the importance of reassessing the diagnosis.Whether the initial episode represented SLE or TAFRO syndrome with lupus-like features remains uncertain.Careful diagnostic reassessment is essential when the clinical course deviates from the expected trajectory.