INTRODUCTION: Thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and 
organomegaly (TAFRO) syndrome is a severe subtype of idiopathic multicentric 
Castleman's disease, characterized by thrombocytopenia, anasarca, fever, 
reticulin myelofibrosis, and organomegaly. Renal complication of this disease 
can be life-threatening and sometimes requires hemodialysis, but it has not been 
elucidated in detail.
METHODS: Case-series was designed to evaluate the renal histology of patients 
with TAFRO syndrome treated at our hospital.
RESULTS: Seven patients were eligible to the criteria. All of them had severe 
diuretic-resistant anasarca and 6 of 7 had mild proteinuria (<1 g daily). On 
light microscopy, all patients showed glomerular endotheliopathy characterized 
by endothelial cell swelling and a double contour of the glomerular basement 
membrane with mesangiolysis or mesangial loosening. Immunofluorescent staining 
and electron microscopy did not detect immune deposits in any patient. Electron 
microscopy revealed endothelial cell swelling with diffuse expansion of the 
subendothelial space, loss of mesangial architecture, and loss of endothelial 
cell fenestrations. Treatment with glucocorticoids and molecular-targeting 
agents, including tocilizumab and rituximab, improved renal dysfunction and 
anasarca. In 4 of 7 patients with persistent thrombocytopenia, hemorrhagic 
events occurred despite platelet transfusion or thrombopoietin receptor 
antagonist therapy.
CONCLUSION: Severe diuretic-resistant anasarca with mild proteinuria and severe 
glomerular endotheliopathy were common characteristics of renal dysfunction due 
to TAFRO syndrome. In addition, endothelial changes mediated via interleukin 
(IL)-6 and vascular endothelial growth factor (VEGF) that lead to vascular 
hyperpermeability and water leakage might contribute to anasarca, because 
molecular-targeting therapy directed against IL-6 or VEGF improved renal 
dysfunction and severe endothelial damage.