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M1 Histopathology Labs with Virtual Slides
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Histopath Lab 4:
Inflammation II

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


INFLAMMATION II


Slide 21 [WebScope][ImageScope]

Perivascular Soft Tissue: This specimen comes from a patient who had a surgical procedure in the region many weeks before this specimen was obtained.

  • At low magnification, you will note cross sections of a large blood vessel with adjacent dense collagenous tissue surrounding some very other material, which appears as clusters of grayish fibers cut longitudinally and in cross-section. Under closer inspection you will note that the clusters of material are surrounded by a population of striking multi-nucleated giant cells. The propensity of these giant cells to surround and engulf foreign material is obvious. A scattering of other inflammatory cells is also present.
  • What is the origin of the multi-nucleated giant cells?
  • Would all foreign material evoke this type of response?
  • Under special light filtration (polarization) the foreign material stands out much more. What do you think it is?

 

Slide 20 [WebScope][ImageScope]

Spleen:

  • At low magnification, you can identify the capsule of this organ—a thin layer of pink collagen. In this case, the usual splenic architecture of red and white pulp is largely replaced by multiple pink staining nodules, each with a surrounding blue halo of inflammatory cells. Closer inspection reveals that each of these nodules consists of an aggregate of large, peculiar looking macrophages with lots of cytoplasm (called “epithelioid” cells, because of their resemblance to true epithelial cells, which also usually have abundant cytoplasm), as well as multinucleated giant cells. Each of these nodular masses is surrounded by a rim of lymphocytes.
  • What are each of these lesions called?
  • What are causative agents of these lesions? How could you investigate possible causes of these lesions?

 

Slide 22 [WebScope][ImageScope]

Colon: This specimen was obtained at autopsy of a patient who had a gastric (“peptic”) ulcer which penetrated the gastric wall, leading to spillage of gastric contents into peritoneal cavity.

  • Try at low magnification to identify the layers of the colonic wall. In this case, the appearance of the mucosa is due to postmortem “self-digestion” (autolysis), which leads to a loss of the normal mucosal detail. Autolysis is characteristically lacking an inflammatory response, since the tissue death occurred after the death of the patient.
  • Look at the serosal surface, remembering that the normal serosa would consist of a thin and flattened layer of mesothelium over a thin layer of connective tissue. What would you expect might happen to this normal layer when it is exposed to the spilled contents of the GI tract as in this patient? In this case, you can see at higher magnification that the normal mesothelial layer has been destroyed and the outer surface of the colon is instead covered in a layer of pink, amorphous material and inflammatory cells – what kind of exudate is this?
  • Between the exudate and the colonic wall is a zone of proliferating capillaries and fibroblasts with interspersed inflammatory cells. What kind of tissue is this and what process is this tissue undergoing? What caused this tissue to arise here in this case?
  • What does the presence of the granulation tissue tell you about the age of the inflammatory process? What does the persistence of the neutrophils tell you? REMINDER: don’t confuse granulation tissue with a granuloma—they are different processes.
  • Had the patient survived, what would the ultimate fate of the exudate be? What might be the sequelae and complications of this process in a surviving patient?

 

Slide 23 [WebScope][ImageScope]

Vaginal Apex: This specimen was obtained from a 38-year-old woman who had undergone a vaginal hysterectomy some weeks before. During a follow-up examination, a red nodule was noted at the apex of the vagina in the area of the healing incision. This slide contains tissue from that nodule.

  • There is no normal vaginal tissue in this slide. The entire specimen is the result of the inflammatory and reparative process.
  • Looking around the slide, you will notice that the tissue in this instance is basically the same as that layer that we saw beneath the serosal exudate in the preceding case. Basically, the tissue consists of proliferating vessels of various sizes with diffusely interspersed fibroblasts that are embedded in pink intercellular material. This is edematous ground substance in this immature connective tissue. In addition to the fibroblasts, there is a diffuse infiltrate of leukocytes including neutrophils, macrophages, lymphocytes, and especially prominent plasma cells. Be certain that you can recognize each of these cell types.
  • What is the significance to the patient of a lesion such as this in a healing incision?
  • What is the ultimate outcome of this lesion? How does it resolve?

 

Slide 25 [WebScope][ImageScope]

Skin: This 27-year-old patient had a pigmented skin lesion biopsied which turned out to be a melanoma—a malignant tumor made up of the pigment-producing cells of the skin (melanocytes). Because of the potential seriousness of this diagnosis, the patient’s dermatologist recommended a wider excision of the skin surrounding the biopsy site. This resulted in the specimen in this slide, a “wide local” excision of the biopsied area that was done a few weeks after the original diagnosis was made. There is no remaining neoplasm, but there is a scar from the previous biopsy.

  • At low magnification, you can identify the epidermis and, in some areas, the dermal appendages (hair follicles, sebaceous gland, etc). Note that in the central portion of the specimen, dermal appendages are absent and a dense connective tissue “replaces” the dermis. It has a slightly different, grayish staining quality than the normal dermis on either side. What is this histologic finding? Note that the epidermis over the area of scar shows flattening of the normal rete ridge pattern seen towards the ends of the specimen. Why is this area of epidermis flattened?
  • Relate these histologic features to the gross appearance of the area.
  • A quick glance at Slide 26 Slide 26 [WebScope][ImageScope] at the lowest magnification will reveal an abnormal variation on this same theme. This specimen contains a large nodule which developed in a surgical incision. You will note from the shape of the lesion that this was a “knob” projecting from the skin surface, covered with an intact (regenerated) epidermis. At higher magnification, you can see the coarse, glassy collagen. What is this entity? What is the significance of such a lesion?
  • Slide 27 [WebScope][ImageScope] shows another potential complication of healing, namely a traumatic or “amputation” neuroma. This was a nodule that developed in a surgical scar. It consists of a tangle of regenerating peripheral nerve fibers entrapped in dense collagen. At low magnification, the disorganized nerve bundles can be seen as more blue-gray staining areas. At higher magnification, the individual nerve twigs can be seen traversing the dense, pink-staining collagen. Note how the nerve twigs appear to run in many different directions, cut longitudinally and in cross-section. What is the significance of such a lesion?

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