vpm 152 general pathology lab 3 pigments and …people.upei.ca/hanna/cell path gross...
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VPM 152 GENERAL PATHOLOGY LAB 3
PIGMENTS AND OTHER TISSUE DEPOSITS
Dr. Scott McBurney
Department of Pathology and Microbiology
Office 3333N
January 30, 2015
A. Type of necrosis? B. Type of necrosis?
C. Type of necrosis?
D. Morphological
Diagnosis?
E. Type of necrosis?
http://research.vet.upenn.edu/GeneralandSystemicPathology/tabid/3600/Default.aspx
Contralateral testis
Canine testicle with a sertoli cell tumor
(produces estrogen – feminization syndrome)
F. Cellular Adaptation in Contralateral Testis?
http://research.vet.upenn.edu/GeneralandSystemicPathology/tabid/3600/Default.aspx
G. Cellular Adaptation in Brain with Hydrocephalus?
Hydrocephalus
Normal Brain
Photo courtesy of Dr. Daoust
PIGMENTS AND OTHER TISSUE DEPOSITS
• Many pathologic processes are accompanied by
accumulations of material either within the cell
(intracellular) or within the matrix (extracellular).
1) Amyloid - extracellular hyaline substance.
2) Endogenous pigments – melanin and bilirubin.
3) Exogenous pigments – parasite pigments.
4) Pathologic mineralization – dystrophic and
metastatic.
5) Crystals – urate.
1. Amyloid
• A pathologic extracellular proteinaceous substance (95% amyloid fibrils) that is
deposited between cells in many tissues and is resistant to proteolysis. It
compresses adjacent cells, causing atrophy and death from ischemia/compression.
• Amyloid fibrils are insoluble aggregates that result from the self-assembly of
abnormally folded proteins. Typically the abnormal folded protein has excess β
sheet conformational change. Misfolded proteins are normally degraded
intracellularly (proteosomes) or extracellularly (macrophages) but when too much
and/or certain types of misfolded protein produced, amyloid can form.
• Amyloid is deposited by several different pathogenetic mechanisms, and thus
AMYLOIDOSIS should not be considered a single disease; rather, a group of
diseases that share in common the deposition of similar appearing proteins.
• The most common in veterinary medicine is serum amyloid-associated protein
(SAA) an acute phase protein secondary to chronic inflammatory conditions
(REACTIVE SYSTEMIC AMYLOIDOSIS). Reactive systemic amyloidosis is
common in birds, particularly waterfowl, and is frequently associated with chronic
bacterial infections (eg. Tuberculosis).
• Grossly, affected organs (eg. kidneys, liver, spleen and lymph nodes) are often
swollen, enlarged, firm and waxy. Lugol’s iodine can stain the amyloid black in
fresh tissue.
RENAL AMYLOIDOSIS
RENAL AMYLOIDOSIS
HEPATIC AMYLOIDOSIS
HEPATIC AMYLOIDOSIS
2.Endogenous Pigments
a) Melanin
• Insoluble, intracellular brown-black pigment derived from tyrosine.
• Normal in certain tissues (eg. eye and skin-melanocytes) and occurs incidentally at
other sites (MELANOSIS) - aorta, leptomeninges, etc.
• Grossly, dark pigmented area in otherwise normal tissue.
http://research.vet.upenn.edu/systemicpathology/exam4/commonlargeanimallesions/tabid/3648/albumid/6008-41/default.aspx
EOSOPHAGUS TONGUE AND LARYNX
2. Endogenous Pigments
b) Bilirubin
• Bilirubin is the end product of heme degradation by macrophages and most is derived
from the breakdown of senescent erythrocytes.
• Heme → biliverdin (by heme oxygenase in MØ) → uncongugated bilirubin (by
biliverdin reductase in MØ) → binds albumin & transported to the liver → conjugated to
its glucuronide (water soluble) → excreted in bile.
• Abnormal accumulation called ICTERUS or JAUNDICE. Can be:
o Prehepatic – excess production of bilirubin - increased breakdown of
eryrthrocytes (hemolytic diseases).
o Hepatic – failure of uptke, conjugation or excretion of bilirubin – liver diseases
causing hepatocellular damage.
o Post-hepatic – obstruction of bile flow – can be intrahepatic (hepatic bile ducts)
or extrahepatic (common bile duct).
• Grossly, in blood and tissues produces a yellow discoloration.
Diseases and Disorders of the Horse, Saunders, 2003
ICTERUS OR JAUNDICE
Diseases and Disorders of the Horse, Saunders, 2003
ICTERUS OR JAUNDICE
ICTERUS OR JAUNDICE
ICTERUS OR JAUNDICE
ICTERUS OR JAUNDICE
ICTERUS OR JAUNDICE
Photo courtesy of Dr. Andrea Bourque
3. Exogenous
Pigments
a) Parasite Pigments
Fascioloides magna (giant liver
fluke) - black discoloration of tissue
around bile ducts due to “fluke puke”
(iron-porphyrin pigment or parasite
hematin). http://cal.vet.upenn.edu/projects/paraav/labs/lab6.htm
4. Pathologic Calcification (Mineralization) a) Dystrophic Calcification
• Calcification of injured or Damaged/Dying cells.
• Occurs in areas of necrosis or in cells injured from other processes (toxic, vascular,
inflammation or metabolic).
• Grossly, white, irregular areas in tissue that can be dry or gritty (eg. white muscle
disease and fat necrosis).
Photos courtesy of Dr. Martinson
4. Pathologic Calcification (Mineralization) a) Metastatic Calcification
• Calcification of normal cells/tissues due to hypercalcemia/altered Ca2+ Metabolism.
• Causes include: - primary hyperparathyroidism, renal failure / secondary
hyperparathyroidism, vitamin D toxicosis (iatrogenic, rodenticide or plant analogues),
and paraneoplastic syndrome with certain neoplastic diseases (eg. canine apocrine
gland adenocarcinoma of the anal sac and canine lymphosarcoma).
• Grossly, white plaques or streaks in tissues (i.e., particularly gastric and intestinal
mucosa, interstitium of blood vessel walls and basement membranes of many tissues,
especially lung and kidney).
DYSTROPHIC METASTATIC
Vitality of affected
tissue
Necrotic/Degenerate Normal/Viable
Serum calcium level Normal High
Where calcification
begins
Intracellular Extracellular
PATHOLOGIC CALCIFICATION
(MINERALIZATION)
5.Crystals
a) Urates and Uric Acid
• Birds, reptiles and primates lack the enzyme uricase that promotes the oxidation of uric
acid to allantoin. Therefore, in these species, uric acid is the end product of nitrogen
metabolism, so any significant renal dysfunction (including dehydration) can lead to
abnormal extracellular accumulations/deposits of urates which is called GOUT.
• Can be found in and around joints (articular gout) and on serosal surfaces or in tissues
(visceral gout).
• Grossly, chalky white deposits in tissues (tophi) or frosting of crystals on serosal
surfaces.
VISCERAL GOUT
VISCERAL GOUT
VISCERAL GOUT
VISCERAL GOUT
NORMAL
Photo courtesy of Dr. Forzán
VISCERAL GOUT
Photo courtesy of Dr. Forzán