Collapsing glomerulopathy coexisting with membranous glomerulonephritis in native kidney biopsies: a report of 3 HIV-negative patients

Focal and Segmental Glomerulosclerosis and Membranous Nephropathy overlapping in a patient with Nephrotic Syndrome: a case report

Introduction:

Some cases of membranous nephropathy (MGN) present focal segmental glomerulosclerosis (FSGS) typically associated with disease progression. However, we report a case of a patient who seemed to have MGN and FSGS, both primary.

Case presentation:

A 17-year-old female, Caucasian, presenting lower extremity edema associated with episodes of foamy urine and high blood pressure, had physical and laboratorial exams indicating nephrotic syndrome. A renal biopsy was performed and focal and segmental glomerulosclerosis were observed under light microscopy in some glomeruli presented as tip lesion, and in others it was accompanied by podocyte hypertrophy and podocyte detachment in urinary space, compatible with podocytopathy FSGS. Besides, there were thickened capillary loops with basement membrane irregularities due to "spikes" compatible with MGN stage II. Immunofluorescence showed finely granular IgG, IgG4, and PLA2R deposits in capillary loops and, in electron microscopy, subepithelial deposits and foot process effacement. These morphological findings are compatible with FSGS and MGN stage II.

Conclusions:

In the present case, clinical and morphological characteristics showed a possible overlap of primary FSGS and MGN as focal and segmental glomerulosclerosis does not seem to be related with MGN progression but with the podocytopathy FSGS.

Collapsing glomerulopathy in a case of anti-neutrophil cytoplasmic antibody associated vasculitis

Collapsing glomerulopathy (CG) is a pathological entity characterized by collapse and wrinkling of glomerular tuft, podocyte dedifferentiation and hyperplasia. CG may be idiopathic or secondary to other diseases. CG has been described with IgA nephropathy, membranous glomerulopathy, diabetic nephropathy, and lupus nephritis. However, till date there is no report of CG in association with the anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV). Here, we present a case of CG that developed during follow-up in a case of AAV with biopsy proven pauci-immune glomerulonephritis.

Collapsing focal segmental glomerulosclerosis: Current concepts

Collapsing focal segmental glomerulosclerosis (cFSGS), also known as collapsing glomerulopathy is currently classified under the rubric of FSGS. However, its defining morphological features are in stark contrast to those observed in most other variants of FSGS. During the early stage of the disease, the lesion is characterized pathologically by an implosive segmental and/or global collapse of the glomerular capillary tufts, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. With advancement of the disease, segmental and/or global glomerulosclerosis is also observed in association with the collapsing lesions. The etiology of this enigmatic disorder is still elusive, but a growing list of diseases/conditions is being reported in association with this morphological pattern of renal parenchymal injury. The pathogenesis of cFSGS involves discreet epithelial cell injury leading to cell cycle dysregulation and a proliferative cellular phenotype. From the clinical perspective, cFSGS is notorious for its propensity to affect black people, a high incidence and severity of nephrotic syndrome, marked resistance to empirical therapy, and rapid progression to end-stage renal disease. The lesion has also been reported in transplanted kidneys either as recurrent or de novo disease, frequently leading to graft loss. Most cases have been reported in western countries, but the lesion is also being increasingly recognized in the tropical regions. The recent increase in reporting of cFSGS partly reflects a true increase in the incidence and partly a detection bias. There is no specific treatment for the disorder at present. Newer insights into the pathogenesis may lead to the development of targeted and specific therapy in near future. There is an urgent need to increase awareness of the lesion among pathologists and nephrologists, especially those from developing countries, to ensure accurate diagnosis and appropriate managment. With the accumulation of more and more data, it is hoped that the prevailing confusion about the nosological identity of the lesion will also be resolved in a more logical way.

Collapsing glomerulopathy in Portugal: a review of the histological and clinical findings in HIV and non-HIV patients

BACKGROUND

Collapsing glomerulopathy (CG) is a glomerulonephritis seen in association with human immunodeficiency virus (HIV) infection, known as HIV-associated nephropathy (HIVAN), and less frequently observed in non-HIV-infected patients. Method. The aim of this study was to review the histological and clinical findings of all CG diagnosed since 1981 in our laboratory. Result. Since 1981, 18 kidney biopsies with collapsing features were diagnosed among 6130 biopsies performed: 72.2% (n = 13) males, mean age 33.8 ± 9.7 years, 61.1% (n = 11) of black ethnic origin. HIV infection was present in 10 patients. Mean serum creatinine (Scr) was 4.7 ± 2.5 mg/dL, and mean proteinuria was 6.1 ± 5 g/24 h. Both HIVAN and non-HIVAN patients were similar in terms of age, gender and dialysis requirement. In the HIVAN population, African origin was predominant and more frequent than in the non-HIVAN population, Scr was higher and proteinuria was less severe. Interstitial infiltrate, interstitial fibrosis and tubular atrophy were severe, and the presence of microcystic dilatation of renal tubules was more common. Immunofluorescence was positive in six patients. In the non-HIVAN population, this histological lesion was related to an infectious illness in 6/8 patients and to the use of illegal oral drugs in one patient. Interstitial infiltrate, interstitial fibrosis and tubular atrophy presented as moderate to severe, and tubular atrophy correlated with dialysis requirement. Mesangial proliferation was present in 3/8 patients, with C3 and IgA deposits.

CONCLUSION

CG is a rare podocytopathy. In this study, the association between infection and CG is evident, and we may suggest that infections could, in a direct or indirect manner, be a trigger of podocyte injury.

Rapidly deteriorating kidney function in a young man previously diagnosed with membranous nephropathy

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