On electron microscopy of renal biopsy, distinctive “basket-weave” appearance of glomerular basement membrane (GBM) seen in:
**Core Concept**
The "basket-weave" appearance of the glomerular basement membrane (GBM) on electron microscopy is a characteristic feature of a specific kidney disease. This appearance is due to the thickening and splitting of the GBM, resulting in a distinctive ultrastructural pattern. The GBM is a critical component of the glomerulus, playing a key role in the filtration of blood.
**Why the Correct Answer is Right**
The "basket-weave" appearance is typically seen in membranoproliferative glomerulonephritis (MPGN), a type of kidney disease characterized by the thickening and splitting of the GBM. This is due to the deposition of immune complexes and complement factors, leading to the activation of the coagulation cascade and the formation of new membrane layers. The GBM's "basket-weave" appearance is a result of the fusion of the original GBM with the newly formed membrane layers.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the "basket-weave" appearance is not a characteristic feature of membranous nephropathy, which is typically associated with a "spike-and-loop" appearance on electron microscopy.
**Option B:** This option is incorrect because focal segmental glomerulosclerosis (FSGS) is characterized by the collapse of glomerular tufts and the formation of sclerosis, but not the "basket-weave" appearance of the GBM.
**Option C:** This option is incorrect because minimal change disease (MCD) is characterized by normal glomerular morphology on electron microscopy, with no thickening or splitting of the GBM.
**Clinical Pearl / High-Yield Fact**
The "basket-weave" appearance of the GBM on electron microscopy is a key diagnostic feature of membranoproliferative glomerulonephritis (MPGN). This ultrastructural pattern is often seen in conjunction with the presence of immune complexes and complement factors in the GBM.
**Correct Answer:** C. Membranoproliferative glomerulonephritis (MPGN)