Schistosoma mansoni infection as a trigger to collapsing glomerulopathy in a patient with high-risk APOL1 genotype

Background

Schistosoma mansoni schistosomiasis (SM) remains a public health problem in Brazil. Renal involvement is classically manifested as a glomerulopathy, most often membranoproliferative glomerulonephritis or focal and segmental glomerulosclerosis. We report a case of collapsing glomerulopathy (CG) associated with SM and high-risk APOL1 genotype (HRG).

Case report

A 35-year-old male was admitted for hypertension and an eight-month history of lower-limb edema, foamy urine, and increased abdominal girth. He had a recent diagnosis of hepatosplenic SM, treated with praziquantel, without clinical improvement. Laboratory tests revealed serum creatinine 1.89mg/dL, blood urea nitrogen (BUN) 24mg/dL, albumin 1.9g/dL, cholesterol 531mg/dL, low-density lipoprotein 426mg/dL, platelets 115000/mm³, normal C3/C4, antinuclear antibody (ANA), rheumatoid factor (RF), and antineutrophil cytoplasmic antibodies (ANCA), negative serologies for hepatitis C virus (HCV) and human immunodeficiency virus (HIV), HBsAg negative and AntiHBc IgG positive, no hematuria or leukocyturia, 24 hour proteinuria 6.56g and negative serum and urinary immunofixation. Kidney biopsy established the diagnosis of CG. A treatment with prednisone was started without therapeutic response, progressing to end-stage kidney disease 19 months later. Molecular genetics investigation revealed an HRG.

Conclusions

This is the first report of CG associated with SM in the setting of an HRG. This case highlights the two-hit model as a mechanism for CG pathogenesis, where the high-risk APOL1 genotype exerts a susceptibility role and SM infection serves as a trigger to CG.

Schistosomiasis mansoni is still a public health problem in Brazil and renal involvement is described. In such cases, a glomerulopathy is the typical manifestation, most often membranoproliferative glomerulonephritis. In the current article, we report a patient with a recent diagnosis of hepatosplenic SM who was admitted for nephrotic syndrome associated with reduced renal function and hypertension. Kidney biopsy established the diagnosis of collapsing glomerulopathy (CG) and molecular genetics investigation identified a high-risk APOL1 genotype (HRG). Of note, HRG has been associated with increased risk to develop CG, and a two-hit model has been proposed for the genesis of this glomerulopathy. According to this model, a HRG represents the increased-susceptibility component, while an infection or other environmental factors could act as triggers for the development of CG. Based on those data and model, our case raises SM infection as a new trigger for this severe form of glomerulopathy. This is the first description of a case of CG associated with SM in a patient with an HRG. This case corroborates the interactive role between genetic and environmental factors in the pathogenesis of CG but also identifies SM infection as an additional trigger for its development.

The first report of molecular characterized BRD4-NUT carcinoma in Brazil: a case report

Background

NUT midline carcinoma is a rare and aggressive subset of squamous cell carcinoma, which is characterized by the translocation of nuclear protein in testis gene that is mostly fused with bromodomain and extraterminal family proteins. We describe here the first Brazilian case of NUT midline carcinoma with BRD4-NUT fusion detected in a next-generation sequencing panel and we present the clinical evolution of this patient.

Case presentation

A 42-year-old Caucasian man was diagnosed with poorly differentiated squamous cell carcinoma of the left maxillary sinus, with negative in situ hybridization for Epstein–Barr encoding region and human papillomavirus genotyping. He received induction therapy, chemoradiotherapy with weekly systemic chemotherapy, and, concurrently, weekly intra-arterial chemotherapy. New imaging evaluation, 1 month after the end of the last treatment, revealed a good partial response in the primary lesion. However, positron emission tomography-computed tomography showed multiple suspicious lesions in his bones and lungs, which were histologically confirmed. He died exactly 2 months after metastatic disease was diagnosed.

Conclusions

NUT midline carcinoma is usually very aggressive. Currently, there is no standard of care for treatment of NUT midline carcinoma. The definitive diagnosis must be by demonstration of NUTM1 rearrangement. Immunohistochemical staining of greater than 50% of tumor nuclei on formalin-fixed paraffin-embedded tissue using the monoclonal rabbit antibody to NUT (clone C52B1), has a specificity of 100%, and sensitivity of 87% for the diagnosis of NUT midline carcinoma. Our case is the first Brazilian case of NUT midline carcinoma with BRD4-NUT fusion.

Female Patient with Alport Syndrome and Concomitant Membranous Nephropathy: Susceptibility or Association of Two Diseases?

Alport syndrome (AS) is a disorder of collagen IV, a component of glomerular basement membrane (GBM). The association of AS and immunocomplex nephropathies is uncommon. This is a case of a 37-year-old woman with family history of X-linked AS, including 4 affected sons. This patient developed full-blown nephrotic syndrome along a 3-month period, a presentation not consistent with AS progression. This scenario suggested an alternative diagnosis. A kidney biopsy was therefore performed, showing membranous nephropathy (MN) in addition to GBM structural alterations compatible with AS. Whole exome sequencing also confirmed the diagnosis of X-linked AS, revealing a heterozygous pathogenic mutation in COL4A5. While a negative serum anti-phospholipase A2 receptor did not rule out a primary form of MN, it was also uncertain whether positive serologic tests for syphilis could represent a secondary factor. It is currently unknown whether this unusual association represents AS susceptibility to immunocomplex-mediated diseases or simply an association of 2 disorders.