Search

We report on a 53-year-old Japanese man diagnosed with gastric Burkitt's monomorphic post-transplant lymphoproliferative disorder (B-PTLD) after endoscopy for gastric discomfort 28 months after the patient underwent renal transplantation in Ethiopia. Serum Epstein-Barr virus (EBV) tests were negative before transplantation, but the tumor cells collected from a gastric biopsy showed positive EBV-encoded small RNAs (EBER) at B-PTLD onset. Intensive treatment started with R(rituximab)-CHOP therapy and continued with DA-EPOCH-R therapy has been effective, and relapse has not yet occurred. Burkitt lymphoma has a poor prognosis, but B-PTLD may be effectively treated with high-dose chemotherapy. This is a rare case of gastric B-PTLD in a Japanese patient.

A 33-year-old Japanese man with no significant past medical history was admitted to our hospital for evaluation of weight gain and pitting edema. A laboratory test confirmed nephrotic-range proteinuria. Renal biopsy showed subepithelial deposits, and membranous nephropathy (MN) was diagnosed. Closer examination clarified an active syphilis infection. After renal biopsy, we prescribed amoxicillin for 8 weeks to treat the syphilis infection. Three weeks later, the patient's proteinuria dramatically decreased. This case is of interest because syphilis can become a cause of acute-onset MN in younger adults, and the incidence of syphilis is increasing in Japan.
.

A 60-year-old Japanese woman with polymyositis (PM) developed hemolytic anemia (hemoglobin of 7.3 g/dL), thrombocytopenia (platelet of 9.1×10 4 /µL), and acute kidney injury (Cre of 4.7 mg/dL) at 14 days after starting steroid therapy. Renal biopsy revealed glomerular endothelial swelling with fibrin thrombi and fragmented erythrocytes in the capillary lumens. Hemolytic uremic syndrome (HUS) with thrombotic microangiopathy (TMA) was diagnosed. Hemodialysis and plasma exchange/plasma transfusion were initiated, but HUS did not subside. After 45 days, the patient died of hemorrhagic respiratory failure. Autopsy showed fibrin thrombi filling the glomerular vascular pole and the small arteries in most glomeruli, resulting in glomerular collapse and glomerular basement membrane (GBM) duplication. Although renal involvement by PM is rare, HUS/TMA should be remembered as one of the serious renal complications of PM.

We investigated a 25-year-old Japanese man who had polycystic kidneys and end-stage renal failure without a positive family history. Ultrasonography revealed enlarged kidneys with increased echogenicity and multiple cystic lesions. MRI showed replacement of both kidneys by cystic lesions without definite walls. Renal biopsy demonstrated interstitial fibrosis, especially at the corticomedullary junction. The residual tubular system showed starfish-like disruption. Tubules with cystic dilation were mainly the distal loop of Henle and the distal tubules since immunohistochemical staining was positive for cytokeratin 7 (the distal loop of Henle and the distal tubule) and Tamm-Horsfall protein (the distal loop of Henle), while being negative for aquaporin 3 (the collecting duct) and CD10 (proximal tubule). Comprehensive genetic analysis identified compound heterozygous missense mutations of NPHP4 with autosomal recessive inheritance since his asymptomatic parents each had a single heterozygous missense mutation of NPHP4. In conclusion, MRI and immunohistochemical analysis of renal biopsy specimens may be useful for evaluation of this disease.
.

A 37-year-old Japanese man with a serum creatinine level of 2.5 mg/dL and hepatomegaly was admitted to our hospital for investigation of renal failure. Magnetic resonance imaging (MRI) showed hepatomegaly with small cystic lesions that had high signal intensity on T2-weighted images. There was no splenomegaly, and the kidneys were nearly normal in size with a few small cystic lesions. Renal biopsy revealed that interstitial fibrosis and tubular atrophy affected 60% of the cortex. There was cystic tubular dilation, mainly affecting the distal loop of Henle and distal tubules, since immunohistochemical staining of the dilated tubules was positive for cytokeratin 7 and Tamm-Horsfall protein but was negative for aquaporin 3 and CD10. Immunofluorescence microscopy and electron microscopy did not demonstrate any immune deposits. Genetic analysis identified two different heterozygous missense variants of PKHD1, while the patient's asymptomatic parents were each heterozygous for a single PKHD1 mutation. Accordingly, autosomal recessive polycystic kidney disease (-ARPKD) due to compound heterozygous PKHD1 mutation was diagnosed. The renal biopsy findings of this patient may be nonspecific, but they were different from the typical renal histology of infantile ARPKD. In conclusion, the renal features of adult-onset ARPKD may differ from those of infantile disease.
.