Examkin

Question

Difficulty: MediumPathology and Biopsy Interpretation

A nephrologist is reviewing renal biopsy reports for four different adult patients who presented with various nephritic or nephrotic syndromes. To establish the correct diagnosis, match each specific glomerular disease with its most pathognomonic histological, immunofluorescence, or ultrastructural finding on renal biopsy.

  • IgA nephropathy (Berger disease)Granular immunofluorescence pattern with prominent mesangial deposition of IgA and C3
  • Membranous nephropathySubepithelial immune complex deposits with 'spike and dome' appearance on silver stain
  • Goodpasture disease (anti-GBM disease)Linear immunofluorescence pattern with diffuse IgG deposition along the glomerular basement membrane
  • Post-streptococcal glomerulonephritisEnlarged, hypercellular glomeruli with subepithelial electron-dense 'humps' on electron microscopy

Answer

IgA nephropathy matches with mesangial IgA deposition; Membranous nephropathy matches with 'spike and dome' appearance; Goodpasture disease matches with linear IgG deposition; Post-streptococcal glomerulonephritis matches with subepithelial 'humps'.
Establishing a definitive diagnosis for primary glomerular diseases relies heavily on identifying distinct biopsy findings. Goodpasture disease is unique for its linear immunofluorescence pattern caused by anti-GBM antibodies. Immune complex diseases produce granular patterns, but their specific location and appearance differentiate them: IgA nephropathy shows mesangial deposits, membranous nephropathy causes a subepithelial 'spike and dome' pattern due to basement membrane remodeling, and post-streptococcal glomerulonephritis presents with large subepithelial 'humps'.

Step-by-Step Solution

1
Differentiate the primary patterns of immunofluorescence presented in the biopsy findings.
Identified one linear immunofluorescence pattern and one granular mesangial immunofluorescence pattern.
Immunofluorescence patterns are critical for distinguishing between direct autoantibody binding (linear) and immune complex deposition (granular).
2
Correlate the linear immunofluorescence pattern with its corresponding etiology.
Matched linear IgG deposition with Goodpasture (anti-GBM) disease.
Anti-GBM antibodies uniformly target the basement membrane, resulting in a smooth, linear pattern.
3
Correlate the mesangial IgA immunofluorescence pattern with its corresponding etiology.
Matched granular mesangial IgA and C3 deposition with IgA nephropathy.
IgA nephropathy is defined by the localized deposition of IgA complexes within the glomerular mesangium.
4
Analyze the remaining ultrastructural findings on electron and light microscopy to match the remaining conditions.
Matched 'spike and dome' with membranous nephropathy and subepithelial 'humps' with post-streptococcal glomerulonephritis.
Subepithelial humps are classic for post-infectious etiologies, whereas the spike and dome pattern indicates basement membrane reaction to subepithelial deposits seen in membranous nephropathy.

Key Concept

Histopathological and Immunofluorescence Diagnosis of Glomerular Diseases
Rate this question

Topics

Pathology and Biopsy Interpretation

More questions from this topic