Renal histology in a patient with TAFRO syndrome: a case report.

An 84-year-old Japanese man was admitted due to anasarca, thrombocytopenia, systemic inflammation, and progressive renal insufficiency, resistance to diuretics, glucocorticoid therapy, and plasma exchange. Renal biopsy showed diffuse endocapillary proliferation and mesangiolysis without any immune deposits. Tocilizumab suppressed systemic inflammation, resulting in improvement of anasarca and renal dysfunction, but thrombocytopenia persisted and platelet-associated IgG antibody was elevated. Although romiplostim was effective for thrombocytopenia, the patient died of aspiration pneumonia after cerebral hemorrhage. Autopsy showed hyaline vascular-type Castleman disease-like lymphadenopathy and reticulin myelofibrosis with an increase of megakaryocytes. Renal finding showed that endocapillary injury improved, and collapsed glomeruli were noted. This patient fitted the criteria for TAFRO (thrombocytopenia [T], anasarca [A], fever [F], reticulin myelofibrosis [R], and organomegaly [O]) syndrome. The clinical course suggests that 2 factors, including overproduction of interleukin 6 and autoimmune-mediated thrombocytopenia via thrombopoietin receptor, may have contributed to the pathogenesis of TAFRO syndrome in this patient.