A 58-year-old man presents with nephrotic syndrome. Kidney biopsy shows thickened capillary loops with subepithelial deposits on electron microscopy. Serum anti-phospholipase A2 receptor (anti-PLA2R) antibody is strongly positive. This finding establishes the diagnosis of:

• A Secondary membranous nephropathy due to lupus
• B Primary (idiopathic) membranous nephropathy ✓
• C Minimal change disease
• D Renal amyloidosis

Explanation

The PLA2R is a podocyte transmembrane glycoprotein, and circulating anti-PLA2R antibodies are present in about 70 to 80 percent of patients with primary membranous nephropathy and are absent in secondary forms such as lupus-associated, hepatitis B-associated, or drug-induced disease. Their detection therefore confirms idiopathic disease and can obviate biopsy in appropriate settings. Lupus membranous nephropathy features full house deposits, not anti-PLA2R positivity.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.