1. Kidney: Candidasis Lab 10, Case 1

2. Multifocal punctate lesions visible on the serosal surface (arrows) Don’t confuse these small yellow punctate lesions with the fat that is adherent to the renal capsule.

3. Cut surface of the kidney The multifocal punctate lesions are primarily in the cortex (arrows)

4. Lymph node with three prominent areas of Candida colonies (arrows) Even at this low magnification, the purple-staining yeast and pseudohyphae can be easily seen. This section was stained with PASH, which stains the cell walls of the fungi to make them more visible.

5. One of the Candida colonies from this lymph node The chains of yeast which are termed “pseudohyphae” are apparent at this magnification.

6. Yeasts and pseudohyphae in this focus of Candida organisms

7. 1: Yeast 2: Pseudohyphae

8. Arrows: Candida colonies The pseudohyphae are evident around the periphery of these colonies.

9. Candida colony in the kidney Note the pseudohyphae of the Candida organisms.

10. Adrenal Gland: Histoplasmosis Lab 10, Case 2

11. Section of adrenal gland with several irregularly-outlined areas of necrosis

12. Higher powered view of previous adrenal gland section Shows more clearly the irregularly-shaped area of necrosis (arrows)

13. Area of necrosis (arrows) There is loss of cellular detail within this area. There are inflammatory cells present; however, it is difficult to differentiate the inflammatory cells and the naïve lymphocytes of the adrenal gland, which is a lymph node.

14. Edge of the area of necrosis There is a mild inflammatory infiltrate along the edge of the necrosis.

15. Small (2-5 mm) dark-staining organisms in the cytoplasm of many of these cells (arrows)

16. Same section of tissue as previous slide This section has been stained with methenamine silver, which causes the Histoplasma organisms to stain black (arrows)

17. Oil immersion Silver-stained Histoplasma organisms Some of the organisms appear to be budding (arrows).

18. Lung: Cryptococcosis Lab 10, Case 3

19. Chest X-ray showing the mass (arrow) in the right lower lobe

20. Lung at autopsy Note the areas of emphysema (1) and consolidation (2).

21. Another section showing lung consolidation

22. Lesion from lung seen on x-ray There is very little, if any, inflammatory reaction.

23. Cryptococcal lesion The air spaces are filled with organisms (arrows).

24. Cryptococcal lesion Some of the organisms have been expelled during processing, but some cryptococcal organisms can be seen (arrows).

25. Cryptococcal lesion In this section, numerous cryptococcal organisms (5-10 mm in diameter) can be seen (arrows). Note that there is very little inflammatory reaction.

26. Cryptococcal organisms within a lesion Some of the organisms have a well-defined halo (arrows) due to the mucopolysaccharide coat which surrounds them.

27. Cryptococcal organism Shows more clearly the nucleus surrounded by the large extracellular capsule (arrows).

28. Lung section stained with Alcian blue, which stains the acidic glycosaminoglycans making up the coat of the cryptococcal organisms.

29. Lung section stained with Alcian blue The mucopolysaccharide capsule shrinks during processing with this stain, thereby producing a shrunken central appearance with the formation of spikes around each organism.

30. Touch prep of fresh lung tissue that was allowed to air dry and then stained to show the mucopolysaccharide capsule around the cryptococcal organisms (arrows).

31. Lung: Blastomycosis Lab 10, Case 4

32. Gross photograph of lung showing areas of necrosis and consolidation

33. 1: Area of necrosis 2: Areas of consolidation 3: Satellite lesions

34. Lung tissue Arrows: Areas of consolidation

35. Lung section with pleura The pleura (1) is thickened and contains inflammatory cells and fibrin. The areas of consolidation (2) are dense and filled with inflammatory cells.

36. Lung section with pleura The pleura (arrows) is thickened and contains inflammatory cells and fibrin. The alveoli are filled with inflammatory cells. Some of the alveolar septa are congested with red blood cells.

37. Shows what appears to be inflammatory cells filling the alveoli At this magnification, numerous round bodies (arrows) that look like inflammatory cell nuclei can be seen. However, on closer examination, some of these round bodies are surrounded by clear halos.

38. An alveolus filled with numerous round bodies up to 25 mm in diameter. Some of these double- contour bodies (1) have a dense center and a clear halo. These are the Blastomyces organisms. The typical B. dermatitides organism is smoothly-outlined with a central, densely basophilic cytoplasm surrounded by a clear halo. When stained with H & E, the organism is outlined by a relatively thick cell wall. There are also numerous inflammatory cells (2) in the avleolus- neutrophils, lymphocytes, and macrophages- which produce a pyogranulomatous inflammatory reaction.

39. An alveolus filled with Blastomyces organisms This section is stained with PAS to stain the organisms.

40. Blastomyces organism stained with PAS Note the budding organism (arrow). Blastomyces has a characteristic presentation of budding which aids in the diagnosis of the fungus.

41. Blastomyces organism stained with PAS Note the budding organism (arrow) and the pyogranulomatous inflammatory reaction in the background.

42. Carotid Artery: Mucormycosis Lab 10, Case 5

43. Section of carotid artery containing a mural thrombus

44. 1: Wall of carotid artery 2: Thrombus

45. 1: Wall of carotid artery 2: Thrombus 3: Within the wall of the artery and in the thrombus, there are multiple variably shaped clear areas. At this magnification and with this stain, it is impossible to determine what these clear spaces represent.

46. Wall of the carotid artery Note the ribbon-like clear structure with roughly parallel walls (non-septate hyphae) and right-angle branching (arrow). This is the Mucor organism.

47. Wall of the artery and the thrombus Within the thrombus there are multiple variably-shaped clear areas that represent longitudinal sections and cross sections of the Mucor organisms (arrows).

48. Thrombus stained to outline the Mucor organisms (arrows) Note again the ribbon-like morphology and the wide-angle branching.

49. Thrombus stained to outline the Mucor organisms (arrows)