Membranous Nephropathy
Membranous Nephropathy is a common cause of nephrotic syndrome in Caucasian adults. It is characterized by the diffuse thickening of the glomerular capillary wall due to immune complex deposition.
1. Pathological Features
| Examination | Findings |
|---|---|
| Light Microscopy (LM) | Diffuse capillary wall thickening (no hypercellularity). |
| Immunofluorescence (IF) | Granular appearance (IgG and C3). |
| Electron Microscopy (EM) | “Spike and dome” appearance (subepithelial deposits with GBM material protruding between deposits). |
2. Exam Must-Knows
- Primary vs. Secondary: Most cases are primary (idiopathic), often involving antibodies against the phospholipase A2 receptor (PLA2R). Secondary causes include SLE, Hepatitis B/C, solid tumors, and certain drugs (NSAIDs, penicillamine).
- Complications: High risk for Renal Vein Thrombosis and other thromboembolic events.
- Course: Variable; some patients have a slow progression to chronic renal failure, while others may have spontaneous remission.
Pathology Board Hint: Whenever you see “Spike and dome” on a board exam, pick Membranous Nephropathy. Also, remember the association with PLA2R antibodies—this is a very high-yield testing point.