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Kidney nontumor
Primary glomerular diseases
Minimal change glomerulopathy
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: Minimal change glomerulopathy[TIAB]
Primary glomerular diseases
Minimal change glomerulopathy
Author: Ana Belén Larqué, M.D., Ph.D.
Editor-in-Chief: Debra Zynger, M.D.
Topic Completed: 8 January 2019
Revised: 8 April 2019
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: Minimal change glomerulopathy[TIAB]
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Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Diagrams / tables | Clinical features | Diagnosis | Laboratory | Prognostic factors | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Immunofluorescence description | Electron microscopy description | Electron microscopy images | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Additional references | Board review question #1 | Board review answer #1 | Board review question #2 | Board review answer #2 | Board review question #3 | Board review answer #3Cite this page: Larqué AB. Minimal change glomerulopathy. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneyminchange.html. Accessed January 21st, 2020.
Definition / general
- Idiopathic glomerular disease that causes nephrotic syndrome
- Little or no light or immunofluorescent microscopic abnormalities
- Diffuse foot process effacement on electron microscopy (BMC Nephrol 2018;19:207)
Essential features
- Renal glomeruli appear normal by light and immunofluorescence microscopy
- Extensive effacement of podocyte foot processes by electron microscopy (hallmark)
- Highly selective proteinuria, mainly albuminuria
- Responds well to treatment with corticosteroids (90 - 95%)
Terminology
- Also called minimal change disease, idiopathic nephrotic syndrome, nil disease, lipoid nephrosis and foot process disease
ICD coding
Epidemiology
- Most common type of nephrotic syndrome in children: 70 - 90%; in adults: 11 - 16%
- Peak incidence in children: 2 - 3 years; in adults: 80 - 91 years
- In children, M:F = 2:1; in adults, M = F
- More common in Caucasians and Asians than African-Americans (Clin J Am Soc Nephrol 2007;2:445)
Sites
- Glomerular disease
Pathophysiology
- Extensive foot process "fusion" appears to be due to epithelial injury with loss of glomerular anionic charge (Kidney Int 1984;25:696)
- Unknown circulating factor that triggers podocyte dysfunction postulated (Pediatr Nephrol 2018;33:1101)
- Minimal change disease, diffuse mesangial hypercellularity and focal segmental glomerulosclerosis may be a continuum of the same disease (Kidney Int 2004;65:1690)
Etiology
- Usually idiopathic, especially in children (Clin J Am Soc Nephrol 2017;12:332)
- Secondary forms due to virus, drugs, allergic reactions, immunologic diseases and neoplasia at all ages (BMC Nephrol 2018;19:162, Intern Med 2014;53:1131, Case Rep Nephrol 2015;2015:987212, J Surg Oncol 2010;102:704)
- Rarely familial (gene mutations: NPHS2, dysferlin) (Semin Nephrol 2003;23:141)
Diagrams / tables
Images hosted on other servers:
Lipoid nephrosis
Clinical features
- Nephrotic syndrome
- Proteinuria selective for albumin, causing hypoalbuminemia leading to severe edema
- Lipiduria, hypercholesterolemia but usually no hypertension, no hematuria and no azotemia
- Microhematuria (10 - 30%)
- Can present as acute renal insufficiency in adults (Clin J Am Soc Nephrol 2017;12:332)
Diagnosis
- Nephrotic syndrome with little or no light or immunofluorescent microscopic abnormalities
- Diffuse foot process effacement on electron microscopy
Laboratory
- CD80 in urine may be a marker (Pediatr Nephrol 2015;30:309)
Prognostic factors
- Rarely, if ever, leads to end stage renal disease without development of focal segmental glomerulosclerosis
- Adults with minimal change disease and acute renal failure also usually fully recover (Medicine (Baltimore) 2014;93:e300)
- Relapses common and often lead to steroid dependence
Case reports
- 2 and 15 year old boys with steroid responsive nephrotic syndrome complicated by cerebral venous sinus thrombosis (Nefrologia 2015;35:497)
- 29 year old woman with type I neurofibromatosis and complete remission after neurofibroma resection (Korean J Intern Med 2017;32:186)
- 33 year old man with severe chronic sinusitis (Intern Med 2015;54:2373)
- 50 year old woman with minimal change disease after a type B influenza infection (BMC Nephrol 2018;19:162)
- 68 year old man with marginal zone MALT lymphoma manifesting as nephrotic range proteinuria (Clin Nephrol 2016;85:184)
Treatment
- Corticosteroids
- Immunosuppressive agents in steroid resistant cases (cyclophosphamide, rituximab, abatacept) (Kidney Int 2013;83:511, Pediatr Nephrol 2015;30:469)
Gross description
- Enlarged, waxy yellow cortex due to lipid accumulation in proximal tubules
Microscopic (histologic) description
- Glomerulus normal by light microscopy except for variable podocyte hypertrophy
- Protein reabsorption droplets in tubules (Zhou: Silva's Diagnostic Renal Pathology, 2nd Edition, 2017)
Microscopic (histologic) images
Contributed by Ana Belén Larqué, M.D., Ph.D.
Aggregates of lipid laden macrophages
Images hosted on other servers:
Relatively normal
appearing glomeruli
and lipoid nephrosis
Immunofluorescence description
- Negative except for variable focal IgM ± C3
Electron microscopy description
- Extensive foot process effacement (foot processes retract into cell bodies, not actually fusion)
- Microvillous transformation of epithelial cells, cyst formation
Electron microscopy images
Contributed by Ana Belén Larqué, M.D., Ph.D.
Hypertrophic podocytes
Images hosted on other servers:
Foot process effacement
Molecular / cytogenetics description
- Rarely familial (Semin Nephrol 2003;23:141, Hum Mol Genet 1995;4:2155, J Am Soc Nephrol 2002;13:388)
- Histologic findings of focal segmental glomerulosclerosis or more rarely minimal change glomerulopathy are a part of the autosomal recessive steroid resistant nephrotic syndrome
- Mutations in NPHS2 have been detected in both familial and sporadic steroid resistant nephrotic syndrome
- NPHS2 gene, formerly SRN1, encodes podocin, a protein that is almost exclusively expressed in glomerular podocytes
Sample pathology report
- Left kidney, biopsy:
- Minimal change glomerulopathy
- Adequacy: adequate (cortex 85%, medulla 15%)
- Microscopic description: 19 glomeruli showed normal size and cellularity. There is no interstitial inflammation and no significant interstitial fibrosis or tubular atrophy. Tubules are preserved, without significant evidence of injury. Small arteries and arterioles show minimal interstitial fibrosis. There is no vasculitis.
- Immunofluorescence microscopy:
- Number of glomeruli: 4
- There were no deposits of IgA, IgM, IgG, C3, C1q or fibrin
- Electron microscopy: Extensive effacement of the foot processes covering over 80% of the glomerular capillary surface. The glomerular basement membrane showed normal thickness and a generally smooth contour. No electron dense deposits were noted on the glomerular capillary basement membranes or mesangial areas. The mesangial area contained normal amounts of matrix and cells.
Differential diagnosis
- Focal segmental glomerulosclerosis:
- Segmental hyalinosis or synechiae to Bowman capsule, interstitial fibrosis or tubular atrophy
- Cases with unsampled glomerulosclerosis may be misdiagnosed as minimal change disease
- Mesangial glomerulonephritis:
- Early mesangial glomerulonephritis can be indistinguishable on light microscopy
- Positive immunofluorescence and electron dense subepithelial deposits on electron microscopy
- Chyluria:
- Normal podocytes with heavy proteinuria
- IgA nephropathy:
- Minimal change disease could be superimposed on IgA nephropathy
Additional references
Board review question #1
Which of the following is true about minimal change glomerulopathy?
- Interstitial inflammation and fibrosis are usually absent
- It is the most common type of nephrotic syndrome in adults
- Monoclonal antibody therapy should be the first line therapy
- Pretreatment biopsy is always done
Board review answer #1
Board review question #2
Which of the following signs and symptoms is common in minimal change disease?
- Azotemia
- Hypertension
- Macrohematuria
- Selective proteinuria
Board review answer #2
Board review question #3
Which of the following renal lesions is most likely to be present in minimal change disease?
- Acute tubular necrosis
- Glomerular crescent formation
- Mesangial immune complex deposition
- Podocyte foot process effacement
Board review answer #3
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