Different effects of rituximab on a native kidney and a post-transplant kidney with recurrence of focal segmental glomerulosclerosis.

We present the case of a 29-year-old woman with focal segmental glomerulosclerosis (FSGS) who was treated with rituximab administration under different conditions for refractory nephrotic syndrome and posttransplant FSGS recurrence. At the age of 13 years, she developed FSGS, which followed a refractory clinical course, and eventually necessitated her to undergo plasmapheresis and receive rituximab at the age of 25 years. However, both therapies were ineffective, and she subsequently had progressive renal failure, for which dialysis was initiated at the age of 26 years. At the age of 28 years, she received a renal transplant from a living donor. However, nearly 1 year after the transplantation, nephrotic-range proteinuria was observed and FSGS recurrence was confirmed via biopsy of the transplanted kidney. Plasmapheresis resulted in complete remission, which was maintained by rituximab administration, and the patient followed a favorable course. To date, there have been no reports on the effect of rituximab on both the native kidney and post-transplant FSGS recurrence in the same patient. Interestingly, this case showed different responses to rituximab administration.

Proximal Tubulopathy With Fibrillary Inclusions: A Rare Manifestation of Lymphoma-Associated Monoclonal Gammopathy of Renal Significance (MGRS).

Light chain proximal tubulopathy is a rare M-proteinemia-related nephropathy. The inclusions, composed of light chains in light chain proximal tubulopathy, are generally crystalline, and most exhibit a rhombic shape. Noncrystalline structures, such as rods or needle shapes, may also be present. In our patient, one of the noncrystalline structures, fibrillary inclusions in the cytoplasm, were observed, as previously reported in only 4 patients whose primary disease was either multiple myeloma or monoclonal gammopathy of renal significance. This is the first report involving lymphoma. Early diagnosis of light chain proximal tubulopathy is important because those who undergo chemotherapy have an improved kidney prognosis. However, in cases of kidney involvement with blood disorders, thrombocytopenia is often present. Therefore, in our case, open kidney biopsy was selected. Noncrystalline light chain proximal tubulopathy is believed to be less likely to cause Fanconi syndrome. However, Fanconi syndrome was observed in 3 of the 4 patients with fibrillary inclusions. In our case, hypouricemia was improved by chemotherapy, suggesting that the patient presented with Fanconi syndrome. Noncrystalline light chain proximal tubulopathy with fibrillary inclusions may cause Fanconi syndrome, similar to crystalline light chain proximal tubulopathy. We report a case of light chain proximal tubulopathy with fibrillary inclusions complicated by low-grade B-cell lymphoma in which early treatment was successful.

A case of a maintenance hemodialysis patient with autosomal dominant polycystic kidney disease who underwent living donor liver transplantation alone due to refractory liver cyst infection.

Liver cysts are observed in 83% of cases of autosomal dominant polycystic kidney disease (ADPKD). Although not as prevalent as renal cyst infection, liver cyst infection is a serious complication that is sometimes difficult to treat. We report the case of a maintenance hemodialysis patient with ADPKD who received a living donor liver transplantation alone (LDLTA) due to refractory liver cyst infection. The patient was a 67-year-old Japanese man who developed fever and right-side abdominal pain, and liver cyst infection was suspected. Treatment with multiple antibiotics was ineffective. Many liver cysts were observed on magnetic resonance imaging scans and a cyst in liver segment S6, which produced the strongest signal variation, was drained. The fever subsided temporarily, but multiple infected liver cysts were observed on follow-up imaging examination; 4 months later, hepatectomy and LDLTA were performed. Although LDLTA due to refractory liver cyst infection in maintenance hemodialysis patients with ADPKD is risky and should be carefully considered, it may be the only effective treatment.