Cellular Pathology
Histopathology Lab #2
(web)
Paul Hanna Jan 2018
Clinical History:
• a necropsy was performed on an aged cat
• the gross pathological changes included:
widespread subcutaneous edema
ascites
hydrothorax
multiple, pale, wedge-shaped lesions in kidneys
Slide #91
• tissues were sent to AVC for histopathologic examination
Well demarcated pale wedge shaped lesion in renal cortex; with base of
the wedge near the capsule and apex near cortico-medullary junction.
Note – size of the infarct
depends on caliber of vessel
that becomes obstructed
Normal kidney, gross sagittal section, cat (above left) and normal histology of the kidney
Well demarcated pale
wedge shaped lesion in
renal cortex; with base
of the wedge near the
capsule and apex near
cortico-medullary
junction.
Slide #91
Within the affected
area the basic
architectural
arrangement of the
glomeruli and tubules
is apparent however
the cells resemble an
eosinophilic shadow
(ghost-like remnant)
of the original cells.
Surrounding layer of
inflammatory cells;
most of which are
degenerate.
Within the affected
necrotic area the
basic architectural
arrangement of the
glomeruli and tubules
is apparent however
the cells resemble an
eosinophilic shadow
(ghost-like remnant)
of the original cells.
Surrounding layer of
inflammatory cells;
most of which are
degenerate.
Within the affected
necrotic area the basic
architectural
arrangement of the
glomeruli and tubules
is apparent however
the cells resemble an
eosinophilic shadow
(ghost-like remnant) of
the original cells.
Most nuclei are
inapparent (karyolysis)
Surrounding layer of
inflammatory cells;
most of which are
degenerate.
Within the affected
necrotic area the basic
architectural arrangement
of the glomeruli and
tubules is apparent
however the cells
resemble an eosinophilic
shadow (ghost-like
remnant) of the original
cells. Most nuclei are
inapparent (karyolysis)
Slide #91
Morphologic Diagnosis: Renal infarct (locally extensive necrosis of the renal cortex)
Comment:
• an interlobar or arcuate renal artery was obstructed by a thrombus / thromboembolus resulting in ischemia to the renal parenchyma and subsequently coagulation necrosis.
• layer of inflammatory cells at the margin of the infarct is a response to the dead tissue.
Description:
• on low-power this section of kidney contains an irregular, wedge-shaped pale eosinophilic area which has a basophilic border.
• the apex of this triangular area is within the medulla, while the base is approximately 1-2 mm from the capsular surface.
• the inner material is composed of ghost-like remnants of the renal parenchyma (coagulation necrosis of tubules, glomeruli, etc) and the whole area is surrounded by a thick layer of inflammatory cell debris.
• there is an increase of fibrous connective tissue and some inflammatory cells within the interstitium of the remainder of the renal cortex (pre-existing nephritis).
Case #95
History:
• three-year-old, DLH, female, cat
• ear margins turning dark color over last few weeks (February)
Note, necrotic ear tips (above) and sloughing of
necrotic ear tip on cat (right) with some “raw”
(granulation tissue) along the remaining margin.
Base of pinna
normal tissue Necrotic
tip of ear
Layer of
inflammation
separating
viable from
necrotic tissue
Base of pinna – normal tissue
Base of pinna – normal tissue
Case #95
Necrotic
tip of ear
Layer of
inflammation
separating
viable from
necrotic tissue
Case #95
Necrotic
tip of ear
Layer of
inflammation
separating
viable from
necrotic tissue
The affected region appears as an acidophilic shadow (ghost-like remnant) of the normal tissue /
cells (ie architecture intact but acidophilia and karyolysis). Note – melanin pigment has persisted.
The affected region appears as an acidophilic shadow (ghost-like remnant) of the normal tissue /
cells (ie architecture intact but acidophilia and karyolysis). Note – melanin pigment has persisted.
Case #95
Description:
• on low-power examination a section of pinna shows hypereosinophilia of the peripheral half of
the section with a zone of basophilia at the junctional zone.
• on higher magnification, the affected region appears as an acidophilic shadow (ghost-like
remnant) of the normal tissue / cells (ie architecture intact but acidophilia and karyolysis).
• the basophilic zone, between viable and necrotic tissue, consists of inflammatory cell debris.
Morphologic Diagnosis: Locally-extensive necrosis (infarction) of the pinna
Comment:
• lesion is consistent with frostbite (ie dry gangrene = coagulation necrosis of an extremity).
• the cold temperature caused vasoconstriction (ie reduced blood supply to the ear tip) which
resulted in ischemic coagulative necrosis (= infarction) of the ear tip.
Clinical History:
• sudden death in a 1-month-old lamb.
• at necropsy the lamb was in good body condition, the majority of skeletal muscles
& left ventricle wall had numerous irregular patchy areas of white discoloration.
• a moderate amount of edematous fluid was present within the thoracic and
abdominal cavities as well as in ventral dependent areas (ie subcutaneous edema
of limbs and ventral abdominal wall).
Case #60
Gross images from a similar case
with skeletal muscle lesions (above)
and myocardial lesions (right).
Skeletal muscle – longitudinal sections Skeletal muscle – cross sections
Three segments of
skeletal muscle from
affected lamb
Case #60
Case #60
note –
fragmentation
and
mineralization
of necrotic
myocytes
Inflammatory
cells (mostly
macrophages)
removing
necrotic cells.
Fragmented
hyalined
myofiber
Fragmented mineralized myofiber
(mineralization is recognized as basophilic
granularity and clumps on H&E staining)
Inflammatory cells (mostly
macrophages) removing
necrotic material.
Case #60
Description:
• the skeletal muscle changes vary in the 3 sections of slide #60 in regards to severity.
• severe lesions are characteristic of coagulation necrosis; ie loss of myofibers with many
remaining myofibers showing fragmentation, intensely eosinophilic staining of cytoplasm
(hyalinization & loss of striations) and often pyknotic nuclei with aggregates of basophilic,
granular material (mineralization).
• there are frequently many mononuclear cells around myofibers (ie phagocytosis by
macrophages).
• if you examine the slide you will note in some areas there are many clusters of enlarged
myofiber nuclei which are indicative of regeneration myofibers.
Comment:
• the history and lesions are characteristic of nutritional myopathy (“white muscle disease”) due
to deficiency of selenium &/or vitamin E.
Morphologic Diagnosis: Myopathy, necrotizing, severe with mineralization
Signalment:
• one-year-old male sheep.
Clinical History:
• brief history of neurological signs prior to euthanasia.
• at necropsy, a large abscess was found in the pituitary fossa and a suppurative
exudate was present in the meninges of the brainstem.
• tissues were taken for histopathology including the pituitary gland.
Case #19
Thick dry pus (purulent / suppurative exudate) filling pituitary
fossa (sella turcica). Note if the pus was less thick (ie more
liquid) pus it would have oozed out of this area and we would
not be able to capture it in a histologic section.
Acidophilic regions are areas of thick dry pus (liquefactive necrosis)
with surrounding basophlic zones of degenerate inflammatory cells
(predominately neutrophils). Note if it was less thick (ie more liquid) pus
it would have oozed out of the tissue and these spaces would be empty.
Acidophilic regions are areas of liquefactive
necrosis. On gross exam this would be a
thick purulent / suppurative exudate (pus)
Surrounding basophlic zones of
degenerate inflammatory cells
(predominately neutrophils)
Areas of viable
pituitary gland
Acidophilic region of liquefactive necrosis
(mostly necrotic neutrophils). Note complete
loss of cellular detail (ie amorphous)
Surrounding basophlic zone of degenerating
neutrophils which eventually “liquify” to form the bulk
of the necrotic material
Acidophilic region of liquefactive necrosis
(mostly necrotic neutrophils admixed with
bacteria). Note complete loss of cellular
detail (ie amorphous)
Surrounding basophlic zone of
degenerating neutrophils which
eventually “liquify” to form the bulk of
the necrotic material
Fibrous capsule beginning to
form in attempt to “wall off”
this inflammatory process
Myriads (massive numbers) of bacteria are admixed among the necrotic
material. They aren’t resolved well in this H&E stain, however a Gram
stain of this section would make them more distinctive)
Zone of degenerating neutrophils which
eventually “liquify” to form the bulk of the
necrotic material (lots of enzymatic digestion)
Morphologic Features:
• the majority of normal pituitary tissue is destroyed by the inflammatory reaction.
• the reaction consists of multifocal to coalescing areas of amorphous eosinophilic material
(liquefactive necrosis) which are surrounded by layers of inflammatory cells (mostly
degenerate neutrophils) and then bands of fibrous connective tissue.
• the inflammatory cells are predominately neutrophils with fewer macrophages, lymphocytes
and plasma cells.
• large numbers of bacteria are admixed with the inflammatory cell debris.
Case #19
Morphologic Dx: Pituitary abscess
(hypophysitis, suppurative, locally extensive, chronic, severe)
Comment:
• neurologic signs were likely due to accompanying meningitis.
• Trueperella pyogenes is a frequent cause of abscesses, mastitis & pneumonia in farm animals
• bacteria reach the pituitary hematogenously (via blood stream) or locally from the oropharynx.