Renal Journal Club

Idiopathic nodular glomerulosclerosis is a distinct clinicopathologic entity linked to hypertension and smoking

Authors: Markowitz GS, Lin J, Valeri AM, et al.

Publication: Hum Pathol 33: 826-835, 2002

Idiopathic nodular sclerosis mimics diabetic glomerulosclerosis, but occurs in patients with no clinical evidence of diabetes mellitus.  This study reviews a cohort of these patients biopsied between 1996 and 2001.  The patients were more often older, Caucasian, and male.  They presented with renal insufficiency, proteinuria often nephrotic-range, and usually had hypertension, hypercholesterolemia and were smokers.  The renal biopsies were characterized by diffuse nodular mesangial sclerosis, thickened basement membranes and arterial sclerosis.  Combined afferent and efferent arteriolar hyalinosis, once thought to be diagnostic of diabetic damage can also be seen. Immunofluorescence showed low intensity linear staining of all basement membranes in nearly half of the cases.

C3 glomerulopathy: Clinicopathologic features and predictors of outcome

Authors: Medjeral-Thomas NP, O’Shaughnessy MM, O’Regan JA, et al.

Publication: Clin J Am Soc Nephrol 9; 46-53, 2014

C3 glomerulopathy is characterized by intensely staining glomerular deposits of C3 in the absence of significant IgG deposits.  This study describes the clinicopathologic features of a large British cohort of these patients.  One-quarter of the patients had dense deposit disease (DDD) and three-quarters had C3 glomerulonephritis (C3GN). The  DDD patients were younger, had lower C3 levels and more often had crescentic GN.  The C3GN patients were older, and had more arteriolar sclerosis, and glomerular and interstitial damage.  Those patients older than 16 years, who had DDD or crescents, were more likely to progress to end stage renal disease.

Light chain proximal tubulopathy: Clinical and pathologic characteristics in the modern treatment era

Authors: Stokes MB, Valeri AM, Herlitz L, et al.

Publication: J Am Soc Nephrol 27: 1555-1565, 2016.

Proximal tubular cells contain cytoplasmic monoclonal immunoglobulin in the entity known as light chain proximal tubulopathy (LCPT).  The deposits are usually crystalline, but can form globules or create vacuoles.  This study examines the clinicopathologic characteristics of these two forms of LCPT.  The majority of cases, (87%), were crystalline, kappa-restricted and had acute tubular injury.  One-third of noncrystalline patients had lambda restriction or acute tubular injury.  Antigen retrieval by immunofluorescence was frequently required to demonstrate both crystalline and noncrystalline forms.  Electron microscopy also demonstrated crystals and granules not seen on light microscopy.

Mayo Clinic/Renal Pathology Society Consensus Report on pathologic classification, diagnosis and reporting of GN

Authors: Sethi S, Haas M, Markowitz GS, et al.

Publication: J Am Soc Nephrol 27: 1278-1287, 2016

This consensus report on classifying, diagnosing and reporting glomerulonephritis (GN) recommends grouping these cases into five types: immune-complex GN, pauci-immune GN, antiglomerular basement membrane GN, monoclonal Ig GN and C3 glomerulopathy.  Pathology reports should have a primary and a secondary diagnosis.  The primary diagnosis should include the disease entity or pathogenic type, the pattern of injury and the degree of injury.  The second diagnosis includes separate coexisting lesions.  Detailed guidelines for specific features that should be included in a complete medical renal disease report are included.