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M1 Histopathology Labs with Virtual Slides
The University of Michigan Medical School
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Histopath Lab 3:
Inflammation I

INSTRUCTORS: First click here to
map a drive, then open all of the
WinLab links by clicking this link.

Robbins and Cotran Pathologic Basis of Disease 9th Ed.

Suggested Reading:
Pages 90-90 – Inflammation
Pages 100-110 – Healing
Pages 704 -705 – Pneumonia
Pages 816 – Appendicitis
Page 385-390 – Fungal Infections


Slide 14 [WebScope][ImageScope]

Skin and Soft Tissues of Foot: This specimen is from a 72-year-old woman with vascular insufficiency of a lower extremity. She develops a long-standing ulcer.

  • Under scanning power, note the diffuse cellular infiltrate deep in the section, largely in adipose tissue. Note the way that most of the “clouds” of inflammatory cells are spread throughout the subcutaneous adipose tissue, leaving islands of fat cells surrounded by inflammatory cells.
  • What is the prominent inflammatory cell you can identify on these slides? How can you tell? In some areas, there has been karyorrhexis, leaving basophilic bits of nuclear debris.
  • What distinguishes phlegmon or cellulitis from other PMN-containing inflammatory reactions?


Slide 15 [WebScope][ImageScope]

Appendix: This slide shows the appendix of a 16-year-old young man who presented to the emergency room with right lower quadrant abdominal pain. Our colleagues in surgery removed his appendix and we examined it in Pathology. The slide contains one more-or-less longitudinal section of the tip of the appendix, and two cross-sections.

  • How do you recognize the tissue as appendix? One of the cross-sections is nearly normal and
    serves as a good “control” for the others. Which cross-section is normal?
  • In the diseased areas note that the mucosa is either missing or necrotic. In what way does some of this mucosa qualify as gangrenous?
  • Note the presence of a dense inflammatory infiltrate spreading transmurally (through the entire appendiceal wall) to the serosal surface. Is this cellular exudate suppurative or purulent? What is the difference between these kinds of exudate? On some of the serosal surface, the inflammatory cells are mixed with fibrin. What is combination exudate called?
  • How might a person with this condition present clinically? What is the correct treatment?
  • What complication might be produced by the transmural inflammation? What other consequences might follow appendicitis, especially if treatment is delayed?

Slide 19 [WebScope][ImageScope]

An “Unknown”: What’s going on here? It’s a variation on a basic theme that you’ve already learned.

  • First, what organ is this?
  • At low magnification, what looks unusual about this tissue?
  • At higher magnification, describe the abnormalities in any one of the areas where the normal tissue seems to have disappeared. In the center of each of these areas there is abundant cellular debris with just enough viable cells left to identify the predominant cell population.
  • There is a large blood vessel containing a fibrin clot with many clumps of leukocytes. At the edges of this clot there is evidence of “organization” of the clot and a scattering of inflammatory cells. The same is true around many of the destructive lesions within the parenchyma.
  • Can you imagine the gross appearance of this tissue? Can you devise a clinical scenario that might account for what you have seen on this slide?


Slide 16 [WebScope][ImageScope]

Lung: This specimen comes from a patient who was hospitalized for several days in a comatose state before death. On postmortem examination, his lungs were heavy. Clear and milky fluid bubbled up on the cut surfaces when they were pressed with a finger.

  • Under lowest magnification, how does this lung differ from normal? Some of the alveolar spaces, under higher magnification, are seen to contain a pink, acellular material. What is this and where did it come from? Many other alveoli are filled with polymorphonuclear neutrophils. How did they arrive there?
  • The features shown in this slide are those of a purulent pneumonia (or pneumonitis). How would the appearance differ if the process were suppurative?
  • What sort of etiologic agents might be responsible for the pneumonia? How does this patient’s history relate to the pneumonia? Can you relate the histopathologic findings in this case to the likely appearance of the chest x-ray?
  • See if you can trace the course of histologic events that might have taken place had this patient’s pneumonia been successfully treated.
  • What are the possible complications when pneumonia does not resolve?


Slide 16A [WebScope][ImageScope]

Lung: Lung infections are not always bacterial. This slide comes from a patient with compromise of her immune system who died with signs and symptoms of systemic infection.

  • At low magnification, what type of organism can be seen projecting out from the pleural surface?
  • Immunocompromised patients often fall victim to invasive infections with organisms in the environment that are harmless to immunocompetent persons.
  • What are some clinical situations resulting in immunocompromise?



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