A colonoscopy in a hospitalized patient with diarrhea shows tan plaques overlying inflamed mucosa. Histology of a plaque reveals fibrin, mucus, necrotic epithelial cells and neutrophils forming a superficial membrane. This pattern of inflammation is termed:

• A Suppurative inflammation
• B Serous inflammation
• C Pseudomembranous inflammation ✓
• D Granulomatous inflammation

Explanation

When a fibrin, mucin and inflammatory cell exudate forms a superficial membrane over necrotic epithelium, the process is called pseudomembranous (diphtheritic) inflammation, classic for Clostridioides difficile colitis and diphtheria. It is a variant of acute inflammation applied to a mucosal surface, not a separate suppurative process, since frank pus is absent. Granulomatous inflammation requires organized collections of epithelioid macrophages.

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.