Renal involvement in TAFRO syndrome: a review.

Renal involvement in TAFRO syndrome is characterized clinically by general edema with ascites and pleural effusions and a rapidly progressive decline in renal function, with urinary protein levels of usually less than 1 g/day. The histologic features of the kidneys can be described as glomerular microangiopathy characterized by mesangiolysis or mesangial loosening, endothelial cell proliferation, edematous opening in the subendothelial space, and glomerular basement membrane (GBM) doubling due to newly formed basement membrane. Findings such as rupture of the GBM, foot-process effacement or fusion, and epithelial cell loss are rare, and thrombus formation is difficult to identify in the glomerulus. Furthermore, immunodeposits are not seen on immunofluorescence staining or electron microscopy. Unlike adults, in addition to the glomerular lesions described above, adolescents appear to show intimal proliferation of the arterioles and interlobular arteries to the vascular poles and occlusion of the vascular lumen.