Impact of focal segmental glomerulosclerosis over the past decade.

OBJECTIVE: This is a study on the demographics and clinical outcomes including the response to therapy of patients with focal segmental glomerulosclerosis (FSGS) over the past decade. MATERIALS AND METHODS: All histologically proven FSGS cases diagnosed between 2008 and 2018 were analyzed for their clinical, laboratory, and histological characteristics including treatment that could influence the disease progression and renal outcome of these patients. We used the Columbia Classification for FSGS for the renal biopsy. RESULTS: There were two subgroups of FSGS patients; those with nephrotic syndrome and those without nephrotic syndrome. Patients with FSGS with non-nephrotic syndrome had poorer survival rates compared to the nephrotic group. For those without nephrotic syndrome, the indices responsible for progression involved more tubular and blood vessel lesions in addition to glomerular pathology compared to those with nephrotic syndrome. Patients with FSGS with nephrotic syndrome responded to immunosuppressants more favorably compared to the non-nephrotic group, though both groups responded with decreasing proteinuria. The nephrotic group had a better 10-year long-term survival rate of 92 vs. 72% for the non-nephrotic group (log-rank 0.002). The 10-year survival for the whole group of FSGS patients was 64%. CONCLUSION: Our data suggest that in FSGS, one of the significant components of the disease is the vascular and tubular damage, apart from the underlying glomerular pathology, resulting in varying responses to therapy, and the difference is reflected in inherently poorer response to immunosuppressant therapy in those without nephrotic syndrome as opposed to those with nephrotic syndrome, who responded to immunosuppressant therapy (IST) with stabilization of renal function and had less blood vessel and tubular lesions.

Evolution of IgA nephropathy in Singapore over four decades and a comparison of two cohorts from the first and fourth decade.

OBJECTIVE: In this study, we trace the changes in the clinical and histological pattern of IgA nephritis (IgAN) in Singapore as it has evolved over 4 decades and compare the clinical, demographic, histological, and renal outcome of patients with IgAN from the 1st decade and the 4th decade. MATERIALS AND METHODS: This is a retrospective study of all histologically proven IgAN diagnosed between 1976 and 2018. Clinical, laboratory, and histological characteristics between the 1st and the 4th decade, including treatment which could influence the disease progression and renal outcome of these two groups, were compared. We used the Oxford classification to compare the renal biopsy changes for these 2 decades as we were able to retrieve 125 renal biopsy tissues for the 1st cohort of IgAN studied in the 1970s for the comparative study. RESULTS: The commonest clinical presentation throughout the first 3 decades was asymptomatic hematuria and proteinuria (63, 52, and 49%, respectively). In the 4th decade, nephrotic syndrome (31%) was the commonest followed by asymptomatic hematuria and proteinuria (30%), hypertension (21%), and chronic renal failure (11%). The data showed that treatment can modify the Oxford MEST - Crescent scores. Renin-angiotensin system (RAS) blockers modified the S scores, immunosuppressants modified the T and C scores, and combination therapy with RAS blockers and immunosuppressants modified the E, S, and T scores. CONCLUSION: The Oxford MEST classification offers a robust and expressive classification for early and late disease progression with respect to the development of end-stage renal disease (ESRD). E and S seem to be indices of continuing disease activity with progressive glomerulosclerosis, probably still amenable to therapy, but T was a predictive indicator for those destined for ESRD and no longer amenable to therapy.

Changes in primary glomerulonephritis in Singapore over four decades
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This review of 3,289 native kidney biopsies over the past four decades in Singapore documents the changing pattern of biopsy-proven glomerulonephritis (GN)from that of a third world country to that of a developed nation. In the 1st decade, mesangial proliferative GN was the most common form of primary GN, similar to the Asian region. In the 2nd decade, the percentage of mesangial proliferative GN decreased, but membranous GN became more common, as was seen in China and Thailand. In the 3rd decade, focal segmental glomerulosclerosis (FSGS) and membranous nephropathy continued to rise, but it was only recently, in the 4th decade, that FSGS prevalence increased dramatically, although membranous nephropathy continues to increase in some Asian countries. In the last decade in Singapore, Malaysia, and Japan, prevalence of IgA nephritis has decreased but remains the most common GN. The percentage of FSGS continues to increase in many countries like in Italy, United States of America, United Kingdom, China, and Malaysia. We surmise that socioeconomic factors play significant roles in the evolution of the renal biopsy pattern.
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Clear cell sarcomas of the kidney are characterised by BCOR gene abnormalities, including exon 15 internal tandem duplications and BCOR-CCNB3 gene fusion.

AIMS: Clear cell sarcoma of the kidney (CCSK) is a rare paediatric renal malignant tumour. The majority of CCSKs have internal tandem duplications (ITDs) of the BCOR gene, whereas a minority have the YWHAE-NUTM2 gene fusion. A third 'double-negative' (DN) category comprises CCSKs with neither BCOR ITDs nor YWHAE-NUTM2 fusion. The aim of this study was to characterise 11 histologically diagnosed CCSKs immunohistochemically (with CCND1, BCOR and CCNB3 stains) and genetically. METHODS AND RESULTS: By next-generation sequencing, 10 cases (90.9%) had BCOR exon 15 ITDs, with positive BCOR immunoreactivity being found in four (36%) or eight (72%) cases, depending on the antibody clone. By reverse transcription polymerase chain reaction, none had the YWHAE-NUTM2 fusion. The DN case had a BCOR-CCNB3 fusion and strong nuclear CCNB3 and BCOR immunoreactivity. Quantitative polymerase chain reaction showed markedly elevated BCOR expression in this case, whereas BCOR ITD cases had lower levels of elevated BCOR expression. CONCLUSIONS: The majority of the CCSKs in our cohort had BCOR ITDs, and none had the YWHAE-NUTM2 fusion. We verified the strong, diffuse cyclin D1 (CCND1) immunoreactivity in CCSKs described in recent reports. BCOR immunoreactivity was not consistently positive in all CCSKs with BCOR ITDs, and therefore cannot be used as a diagnostic immunohistochemical stain to identify BCOR ITD cases. The DN case was a BCOR-CCNB3 fusion sarcoma. BCOR-CCNB3 sarcoma is typically a primary bone sarcoma affecting male adolescents, and this is the first report of it presenting in a kidney of a young child as a CCSK. The full spectrum of DN CCSKs awaits more comprehensive characterisation.

The Value of Renal Biopsy in Non-Insulin-Dependent Diabetes Mellitus in Singapore over the Past Two Decades.

OBJECTIVE: This study on the prevalence of diabetic nephropathy (DN) and coexistence of non-diabetic renal disease (NDRD) in a cohort of 255 non-insulin-dependent diabetes mellitus (NIDDM) patients aims to determine the value of performing renal biopsies in these patients and elucidate the factors which could affect their progression to end-stage renal disease (ESRD). METHODS: Among 255 NIDDM patients, 93 had DN alone, 69 had NDRD alone, and the remaining 93 had DN plus NDRD (mixed group). The indications for renal biopsy were based on clinical suspicion of superimposed NDRD, including heavy or rapidly increasing proteinuria, renal impairment even though diabetes is of relatively short duration, rapidly declining renal function, and presence of hematuria with dysmorphic red blood cells suggesting presence of glomerulonephritis. RESULTS: The following were predictors of ESRD: high systolic BP at biopsy, longer duration of diabetes, heavy proteinuria, and presence of diabetic retinopathy. Comparing patients in the NDRD group with the DN group and the mixed group, the NDRD group had lower serum creatinine and higher eGFR with lower urinary proteinuria and higher serum albumin at presentation and on follow-up. Kimmelstiel-Wilson nodules were associated with a poorer prognosis leading to a higher occurrence of ESRD among patients with DN. CONCLUSION: Renal biopsy is of value in indicating the prognosis of NIDDM patients with DN based on the diabetic lesions. For NIDDM patients with atypical course and suspicion of associated NDRD, a renal biopsy would enable us to diagnose the underlying NDRD and offer appropriate therapy. Most nephrologists would consider renal biopsy for an NIDDM patient based on clinical indications like atypical clinical course and suspicion of an associated NDRD, but they would not perform a routine renal biopsy like for a CKD patient, unless it is for a research indication.

A Global Evolutionary Trend of the Frequency of Primary Glomerulonephritis over the Past Four Decades.

OBJECTIVE: The pattern of glomerulonephritis (GN) in Singapore is compared with that of 19 other countries to review changing trends in the evolution of GN in Asian, Eastern, and Western countries. METHOD: Three thousand two hundred and eighty-nine renal biopsies in Singapore were reviewed and compared with that of 19 other countries. RESULTS: IgA nephritis is on the decline in many countries, including Singapore, though it still remains the commonest GN in Singapore. Membranous GN that if used to be more frequently present in Western countries has also declined though it continues a rising trend in countries such as Singapore and China. Worldwide, the frequency of focal sclerosing glomerulosclerosis (FSGS) continues to increase in many countries, but in some countries, the frequency is still low with mesangiocapillary GN remaining indigenous. CONCLUSION: Urbanization and socioeconomic changes and less exposure to parasitic and other infestations have transformed Singapore's pattern, which is tending toward that of more developed countries. Antigenic exposure due to lifestyle changes, environmental, and industrial pollution are significant contributory factors that affect the evolutionary trend of GN in many countries. The rising trend in the frequency of FSGS may reflect aging and obesity.

Drug-induced kidney disease--pathology and current concepts.

The kidneys can be damaged by a large number of therapeutic agents. The aim of this article is to discuss the pathological features of drug-induced renal disease as diagnosed by kidney biopsy. The literature is reviewed and cases seen by the authors that have a known drug association are analysed. Mechanisms of injury are varied and all renal structures may be affected. The tubulointerstitial compartment is most frequently involved, but glomerular and vascular lesions are seen in a significant proportion of cases.