A 28-year-old man with nephrotic syndrome undergoes renal biopsy. On light microscopy, 40% of glomeruli show segmental sclerosis with hyaline deposits. Electron microscopy shows segmental podocyte foot process effacement. Immunofluorescence shows segmental IgM and C3 in sclerotic areas. The patient has no family history and no known secondary cause. The most appropriate classification is:

• A Tip lesion variant of FSGS
• B Secondary FSGS due to adaptive changes
• C Collapsing variant of FSGS
• D Primary (idiopathic) FSGS ✓

Explanation

This is classic primary (idiopathic) FSGS with segmental sclerosis affecting a proportion of glomeruli, segmental foot process effacement, and IgM/C3 trapping in sclerotic areas. Secondary adaptive FSGS shows more diffuse foot process effacement and less segmental injury. Collapsing variant shows global collapse and prominent podocyte hyperplasia. Tip lesion variant shows sclerosis at the tubular origin. Primary FSGS often presents with full nephrotic syndrome and responds partially to immunosuppression.

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.