Renal disease presents a unique diagnostic challenge. Clinical manifestations such as proteinuria, hematuria, hypertension, or progressive renal insufficiency reflect functional disturbance but do not define the underlying structural pathology. Unlike many other organ systems, the kidney responds to diverse injuries with a limited repertoire of morphological patterns. The renal biopsy remains the gold standard for diagnosing medical renal diseases. A small core of renal cortex, when systematically processed and interpreted, provides detailed structural, immunologic, and prognostic information that directly influences therapeutic decisions.
Nephropathology encompasses a broad spectrum of disorders:
Many renal diseases share overlapping morphological patterns. Proliferative glomerulonephritis, for example, may result from immune complex deposition, complement dysregulation, or pauci-immune vasculitis, entities that differ fundamentally in pathogenesis and treatment. The role of the nephropathologist is to refine pattern recognition into etiologic classification.
Renal biopsy interpretation is inherently compartment-based and systematic (figure 1).
Evaluation includes:
Renal biopsy interpretation is therefore holistic rather than glomerulocentric.
Immunofluorescence (IF) is one of the most important tools in kidney biopsy evaluation. It helps us “see” immune proteins such as antibodies and complement deposited within the various compartments of a renal biopsy. By identifying what is deposited and where, IF helps us understand the mechanism of injury. DIF is helpful in diagnosing,
In many cases, routine microscopy alone cannot provide the full answer. Immunofluorescence bridges that gap. The pattern of immune deposits transforms what may appear as descriptive structural changes under the microscope into a clear, mechanism-based diagnosis.
Electron microscopy (EM) provides ultrastructural detail that is critical in selected settings. Certain diagnoses including minimal change disease, early membranous nephropathy, hereditary basement membrane disorders, and some complement-mediated diseases may require EM for definitive classification. Thus, ultrastructural examination completes the triad of modern nephropathologic assessment. EM allows evaluation of:
Immunohistochemistry (IHC) further enhances diagnostic specificity. Selected markers assist in:
With the rising burden of kidney diseases, accurate and timely diagnosis through comprehensive kidney biopsy evaluation is essential for effective patient care. We are happy to share that a dedicated Nephropathology Unit has recently been started at our institution, Kauvery hospital, Alwarpet, Chennai.
Figure 1: Renal compartments evaluated on routine Light microscopic examination
Figure 2: Immunofluorescence image illustrating 3+ granular deposits of IgG, C3, Kappa, and Lambda along the glomerular basement membrane in a case of Membranous glomerulonephritis
R Sangamitra MD, PDCC (Renal and Transplant Pathology) Associate Consultant Kauvery Hospital, Alwarpet, Chennai.
Dr Priya Subash Chandra Bose MD, DNB, DipRCPath Senior Consultant Kauvery Hospital, Alwarpet, Chennai.
Dr Sharon Milton, MD, DNB, Consultant Kauvery Hospital, Alwarpet, Chennai.
