10. Langhans’ giant cell. Mycobacteria, which are acid-fast organisms, are present within the giant cell and stain red with a Kinyoun stain.
11. A low power phomicrograph of granulomatous inflammation
12. A granuloma is characterized by a collection of epithelioid macrophages with abundant pale eosinophilic cytoplasm and indistinct cell borders surrounded by a rim of lymphocytes.
15. LEFT : THERE IS A DENSE DERMAL INFILTRATE RIGHT : THE INFILTRATE IS COMPOSED OF FOAMY EPITHELIOID HISTIOCYTES KNOWN AS LEPRA CELLS L E P R O S Y S K I N
18. Granulation tissue is the hallmark of repair. Young granulation tissue is composed of a proliferation of blood vessels and fibroblasts in an edematous stroma. RBC exravasation is prominent because of leaky blood vessels.
19. Older granulation tissue is composed of well-developed blood vessels with an inflammatory infiltrate in the interstitial tissue.
20. SCAR. A scar is composed of parallel bundles of collagen with few fibroblasts and few blood vessels.
21. KELOID. A keloid is composed of thick collagen bundles of whorled arrangement.
22.
23. Whole mount view of chronic peptic ulcer. The external muscle layer has been totally destroyed. Note the overhanging mucosa on one edge and the sloping mucosa on the other.
24.
25. GASTRIC ULCER (PEPTIC ULCER). Chronic active ulcers are characterized by four distinct zones.
26. The first two zones can be seen. The ulcer base is covered by fibrinopurulent debris (zone 1), beneath which is an active suppurative inflammatory infiltrate (zone 2). Zone 1 Zone 2
27. GASTRIC ULCER (PEPTIC ULCER). The third zone of a chronic active ulcer is composed of granulation tissue.
30. Cirrhosis resulting from chronic viral hepatitis. Note the broad scar and coarse nodular surface.
31. CIRRHOSIS. It is the common end point of many disease processes. Fibrous bands diffusely divide the liver into regenerative nodules. A trichrome stain accentuates the nodularity and proves that the bands are made of collagen.
32. ALCOHOLIC CIRRHOSIS (LAENNEC’S CIRRHOSIS). In early alcoholic cirrhosis, bridging fibrosis with entrapped portal tracts is noted. Hepatocytes degenerate, and central veins and portal tracts become trapped in the fibrous scar. Bile plugs and fatty change is noted in the remaining hepatocytic parenchyma.