Healing

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Healing Repair Supplement

• March 25, 2009
• Eileen McKay, MD

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Dear Students I apologize for the delay in
preparing these additional image slides for you.
As I thought about it I realized that some of the
concepts/processes of healing and repair are not
visual in any way. Others certainly are, but we
dont have as many occasions to visualize them as
we prefer to let the body heal thyself without
creating further injury. None the less, I have
two clinical cases from my work load over the
last few weeks that do provide some excellent
images of healing and repair. Images are more
interesting than words to me so I will
incorporate these into future lectures. You may
not benefit directly from that and I know that
some of you will not have a chance to review this
supplement prior to your exam. Your exam
performance is not likely to be affected either
way although this does provide review of some of
the learning objectives. Good luck on your exam.
Enjoy!
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• Case 1 Segmental jejunal resection from a one
  week old male with a history of dilated bowel
  loops detected in utero at 34 weeks gestation and
  continued symptoms of partial bowel obstruction
  postnatally.

Injured region with loss of surface epithelium
(erosion).
Relatively normal villous epithelium
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Simple regeneration can occur in labile tissues.
Notice that the new epithlium is simplified and
does not have the villous architecture of the
normal tissue. If no additional injury occurs it
will regain the villous configuration with
continued growth of the basal layer.
Growth of new epithelium
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Healing of the bowel wall
Injured region with partial loss of the inner
layer muscle fibers and replacement by late
granulation tissue (fibroblasts and new vessels).
A section of healthy bowel wall with the two
layers of the muscularis propria.
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Summary and patient follow-upThe damage to the
muscular wall was indicative of a prior (the in
utero) injury. The mucosal damage was of various
ages with ongoing acute injury and tissue
necrosis. The cause of the initial injury is
unclear. However, the patient has been
subsequently diagnosed with cystic fibrosis. He
may have had impacted meconium that caused
transient bowel obstruction in utero with
compression ischemia and necrosis.
Of interest the presence of thick secretions
causing glandular dilatation is a potential
histopathologic sign of CF and can be seen
throughout the GI tract and in the pancreas.
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Case 2 Reexcision of axillary bed where a prior
lymph node biopsy had been performed. The
patient, a female teenage, was diagnosed with
anaplastic large cell (T cell) lymphoma and
underwent several cycles of chemotherapy.
Follow-up imaging continued to show a hotspot
on PET scanning which led to the reexcision to
investigate the presence of persistent disease.

• Normal tissues present in the axilla include
• Fibroadipose
• Skeletal muscles the traverse the region
• Blood vessels
• Lymph nodes
• Nerves
• Surface skin

• Causes of injury
• Prior surgical procedure
• Chemotherapy
• Presence of metal vascular clips for hemostasis
  (retained foreign body) These must be removed
  from the tissue specimen prior to processing as
  the microtomes cannot cut the clips.

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Normal adipose tissue with delicate fibrous septa
Healed tissue with coalescence of fat vacuoles
and dense fibrosis
Dense fibrosis scar
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Healed skeletal muscle with fibrous scar
interupting fibers. Skeletal muscle is a
permanent tissue that does not usually
regenerate. Permanent tissues that are injured
will heal and be scarred.
Fibrous scar
Muscle fibers
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View at a higher magnification
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Inflammatory cell reaction

• Foreign body giant cells are large macrophages
  that undergo nuclear division without cellular
  division. They are multinucleated and ingest
  foreign substances that cannot be otherwise
  destroyed. The dark brown pigment inside the
  cells is not readily identifiable. Sometimes we
  can identify suture material, fungal elements,
  cholesterol, plant matter.
• Standard macrophages with hemosiderin pigment.
  Hemosiderin is a product of red blood cell
  breakdown (ie. Evidence of previous bleeding at
  site)

Foreign body giant cells
Hemosiderin-laden macrophages
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Chemotherapy effect
The area highlighted represents replacement of a
portion of a lymph node by foamy macrophages.
Presumably the node was partially involved by the
lymphoma which responded to the chemorx. The
cellular debris is then cleaned up by
macrophages.
Residual lymph node
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Higher magnification of the interface
demonstrates pale cells that can be seen to
contain multiple small vacuoles- these are called
foamy or lipid-laden macrophages. The surrounding
small round blue cells are lymphocytes.
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Summary and patient follow-upAll of the
axillary tissue that was excised was submitted
for histologic review. The changes of fibrosis,
chronic inflammation, and foreign body giant cell
reaction were widespread. There was no evidence
of residual lymphoma.