1. BY Dr Abiodun Mark Akanmode.

2. Identify the slide.

3. Acute inflammation Acute inflammation is marked by an increase in inflammatory cells. Perhaps the simplest indicator of acute inflammation is an increase in the white blood cell count in the peripheal blood, here marked by an increase in segmented neutrophils (PMN's).

5. Inflammatory process. Selectins: molecules on leukocytes (L-selectin) and endothelium (E-selectin, P-selectin) act as receptors to provide loose binding for rolling. ICAM-1: intercellular adhesion molecule 1 provides more firm adhesion of the neutrophil, via integrins on neutrophil surfaces, to the endothelium. CD31: this cell to cell adhesion molecule aids in diapedesis. C5a and LTB4: chemotaxis is aided by the C5a component from complement activation, along with leukotriene B4, a product of the lipo-oxygenase pathway of arachidonic acid metabolism.

6. Inflammatory process cont’s. C3b and IgG: opsonins such as the C3b component from complement activation, as well as immunoglobulin G, coat foreign objects such as bacteria to aid in phagocytosis by binding to leukocyte receptors. Myeloperoxidase, lysozyme: after engulfment, killing of bacteria occurs via generation of toxic oxygen species (superoxide) converted to hydrogen peroxide and further converted to a hypochlorous radical by myeloperoxidase from neutrophil granules. In the absence of oxidation, lysozyme from neutrophil granules can form holes in microbial membranes.

7. Identify the slide?

8. Acute appendicitis. This is a photomicrograph of an appendix exhibiting acute inflammation. Note that there are only remnants of mucosal tissue identifiable along the luminal border of this specimen. Note that the surface is very roughened and has deposits of fibrin. The blue color is due to the presence of many inflammatory cells, although at this low power these individual cells cannot be specifically identified.

9. Identif the organ? What is the pathology here?

10. Lobar pneumonia. This is a gross photograph of the lungs from a patient (not the patient from this case) with acute lobar pneumonia. The lung lobe in the upper-right portion of the photograph is affected withpneumonia (arrows)

12. Lobar pneumonia. This is a cut section of a lung from the preceding image. Note the whitish discoloration of the lung tissue in the upper lobe (arrows) compared to the normal collapsed and pink staining lung lobe in the left-hand portion of the photograph. The white discoloration in this tissue is due to infiltration of leukocytes (primarily neutrophils). Note that only one lobe of the lung is involved in this patient with lobar pneumonia.

14. Lobar pneumonia. This is a photomicrograph of alveoli filled with exudate. The alveolar wall outlines (arrows) are barely visible in this section. The alveoli are filled with PMNs, fibrin, and edema fluid. This is a severe acute inflammatory response but the structure of the alveoli remains intact. This tissue is able, with proper treatment, to completely resolve this inflammatory response. Since there has not been necrosis of the lung tissue itself (loss of tissue), this lung could completely recover normal function (resolution).

15. X-ray image of Lobar pneumonia.

16. Identify the slide?

18. Chronic cervicitis. Here is chronic cervicitis. Prolonged acute inflammation or repeated bouts of acute inflammation may lead to the appearance of more mononuclear cells, and chronic inflammation. In this case the inflammation is severe enough to produce mucosal damage with hemorrhage

19. Identify the slide?

20. Granulation tissue. Healing of inflammation often involves ingrowth of capillaries and fibroblasts. This forms granulation tissue. Here, an acute myocardial infarction is seen healing. There are numerous capillaries, and collagen is being laid down to form a scar. Non-infarcted myocardium is present at the far left.

21. What are the components of a granulation tissue.

23. Granulation tissue. At high magnification, granulation tissue has capillaries, fibroblasts, and a variable amount of inflammatory cells (mostly mononuclear, but with the possibility of some PMN's still being present).

24. Identify the slide.

25. Granulation tissue after skin biopsy This is a healing biopsy site on the skin seen a week following the excision, The skin surface has re- epithelialized, and below this is granulation tissue with small capillaries and fibroblasts forming collagen. After a month, just a small collagenous scar will remain.

26. Identify the organ? What is the pathology here?

27. Caseating granuloma. Grossly, a granuloma tends to be a focal lesion. Seen here in a hilar lymph node is a granuloma. Granulomas due to infectious agents such as mycobacteria are often described as "caseating" when they have prominent caseous necrosis.

29. Identify the slide?

31. Caseating granuloma. This is a caseating granuloma. Epithelioid cells surround a central area of necrosis that appears irregular, amorphous, and pink. Grossly, areas of caseation appear cheese-like.

32. Granulomas. The focal nature of granulomatous inflammation is demonstrated in this microscopic section of lung in which there are scattered granulomas in the parenchyma. This is why the chest radiograph with tuberculosis or other granulomatous diseases is often described as "reticulonodular".

33. Identify the slide?

34. Pulmonary granulomas Here are two pulmonary granulomas. Granulomatous inflammation typically consists of mixtures of cells including epithelioid macrophages, giant cells, lymphocytes, plasma cells, and fibroblasts. There may even be some neutrophils.

35. Identify The slide?

36. Langhans type giant cells A giant cell is a mass formed by the union of several distinct cells (usually macrophages), often forming Granuloma. Seen here are two Langhans type giant cells in which the nuclei are lined up around the periphery of the cell. Additional pink epithelioid macrophages compose most of the rest of the granuloma

37. Muchas gracias al final. 37