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Diagnosis:
Focal and segmental glomerulosclerosis, cellular variant

The cellular variant of focal segmental glomerulosclerosis (FSGS) has been recently defined by D'agati et al (Am J Kidney Dis. 2004;43(2):368-82. [PubMed link]) "by the presence of at least 1 glomerulus with endocapillary hypercellularity involving at least 25% of the tuft and causing occlusion of the capillary lumen/lumina. Any segment (perihilar and/or peripheral) may be affected". "Endocapillary cells typically include foam cells, macrophages, and endothelial cells. Other leukocytes, such as neutrophils and lymphocytes, also may be present". "Endocapillary cells occasionally show pyknotic or karyorrhectic debris. Podocyte hypertrophy and hyperplasia are typically identified overlying these lesions, but are not required features".

In the present case the glomerular changes suggest proliferative endocapillary glomerulonephritis (GN), however the clinical presentation and the negativity for immune deposits (only unspecific focal and segmental IgM and C3 deposition) do not support the diagnosis of proliferative GN.

Clinical presentation in the present case, with nephrotic syndrome, is typical of all variants of FSGS. If there was any relation between the previous malaria episode and FSGS in our case we can not determine it with precision. We considere that malaria probably has not relation with the glomerulopathy and it was a casual disease not related to the etiology.

Other authors have defined the cellular lesion as glomerular visceral epithelial cell proliferation with hypertrophy, vacuolization, protein resorption droplets, nuclear changes, and separation from the glomerular basement membrane (Schwartz MM, et al. J Am Soc Nephrol. 1999;10:1900-7. [PubMed link] [Free full text]; Schwartz MM, Lewis EJ. Kidney Int. 1985;28:968-74. [PubMed link]), a change include as collapsing glomerulopathy in the recent FSGS classification by D'Agati et al [PubMed link]. This definition of cellular lesions is controversial and the authors that originally proposed the definition of cellular lesion for podocyte proliferation-hypertrophy do not include the cellular variant, as defined by D'Agati et al, in your descriptions of FSGS variants, and they did not find a single example of cellular variant using D'Agati et al's definition in your series (Schwartz MM. Focal segmental glomerulosclerosis. In: Heptinstall's Pathology of the Kidney, 6º ed. Lippincott Williams & Wilkins, Philadelphia, 2007, pp. 171-173; and Chun MJ, et al. J Am Soc Nephrol. 2004;15:2169-77. [PubMed link][Free full text]).

Prognosis of this variant of FSGS is not completely established; controverses in the definition and classification, and the uncommon diagnosis of this variant are the reasons for a no precise knowledge of the clinical outcome. Stokes et al (with 22 cases) reported that this variant has a clinical outcome intermediate between colapsing glomerulopathy (poor prognosis) and tip lesion (better prognosis) (Kidney Int. 2006;70(10):1783-92. [PubMed link]). Treatment is similar to FSGS not otherwise specified (NOS).

See the chapters Focal Segmental Glomerulosclerosis of our Tutorial.

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Bibliography

• Nair R. Focal segmental glomerulosclerosis: cellular variant and beyond. Kidney Int. 2006;70(10):1676-8. [PubMed link]
• Stokes MB, Valeri AM, Markowitz GS, D'Agati VD. Cellular focal segmental glomerulosclerosis: Clinical and pathologic features. Kidney Int. 2006;70(10):1783-92. [PubMed link]
• D'Agati VD, Fogo AB, Bruijn JA, Jennette JC. Pathologic classification of focal segmental glomerulosclerosis: a working proposal. Am J Kidney Dis. 2004;43(2):368-82. [PubMed link]
• Chun MJ, Korbet SM, Schwartz MM, Lewis EJ. Focal segmental glomerulosclerosis in nephrotic adults: presentation, prognosis, and response to therapy of the histologic variants. J Am Soc Nephrol. 2004;15(8):2169-77. [PubMed link][Free full text]
• Schwartz MM, Evans J, Bain R, Korbet SM. Focal segmental glomerulosclerosis: prognostic implications of the cellular lesion. J Am Soc Nephrol. 1999;10(9):1900-7. [PubMed link] [Free full text]
• Schwartz MM, Lewis EJ.Focal segmental glomerular sclerosis: The cellular lesion. Kidney Int. 1985;28(6):968-74. [PubMed link]
  

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