## Distinguishing Chronic Granulomatous from Non-Granulomatous Inflammation ### Key Histological Difference **Key Point:** The defining feature of granulomatous inflammation is the presence of epithelioid histiocytes (activated macrophages) and multinucleated giant cells (Langhans or foreign body type), which are absent in non-granulomatous chronic inflammation. ### Comparative Table | Feature | Granulomatous | Non-Granulomatous | |---------|---------------|-------------------| | **Epithelioid histiocytes** | Present (hallmark) | Absent | | **Giant cells** | Langhans or foreign body type | Absent | | **Plasma cells & lymphocytes** | Present | Present | | **Fibrosis** | May occur peripherally | Common | | **Vascularity** | Variable | Variable | | **Examples** | TB, sarcoidosis, leprosy, fungal infections | Chronic peptic ulcer, chronic hepatitis, rheumatoid arthritis | ### Epithelioid Histiocytes: Formation & Significance Epithelioid cells are activated macrophages with: - Elongated nuclei (epithelial cell-like appearance) - Reduced phagocytic capacity - Enhanced secretory function (cytokines, growth factors) - Tendency to fuse into multinucleated giant cells **High-Yield:** Epithelioid transformation occurs in response to persistent, poorly degradable antigens (mycobacteria, fungi, foreign bodies) that cannot be cleared by standard macrophage phagocytosis. ### Why Other Features Are Non-Discriminatory - **Plasma cells & lymphocytes:** Present in BOTH granulomatous and non-granulomatous chronic inflammation - **Fibrosis & collagen:** Common end-stage feature in both types - **Vascularity:** Not a distinguishing feature; both may show increased blood vessels **Clinical Pearl:** When you see a granuloma on histology, always think of the classic causes: TB (most common), sarcoidosis, leprosy, fungal infections, and foreign body reactions. [cite:Robbins 10e Ch 2]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.