Degeneration

TYPES OF DEGENERATION

1. Degeneration
DrJenyK John
Asst. Professor (Clinical Pathology)
COVAS, SVPUAT

2. Degeneration
1. Cellular swelling (Cloudy swelling/parenchymatousor
albuminousdegeneration)
•Disturbances of cellular metabolism in which cells swell and cytoplasm of
the cell becomes more granular than normal
•Most common and first reaction of a cell to injury
•Reversible cell injury

3. Etiology
•Mildest irritants-bacterial toxins, rise in body temperature, metabolic
diseases (diabetics), organic and inorganic poisons (lead, arsenic, chloroform
and alcohol) and circulatory disturbances (anemia, infarction, passive
hyperemia and hemorrhage)

4. Cellular swelling
Macroscopically
•Affected organ is slightly enlarged,
edges are slightly rounded and there is
an increase in weight
•Organ appears pale or anemic
•When incised the cut surface bulges
and its capsule draws back slightly
•Cut surface-cloudy, slightly opaque and
appears as if it had been slightly
scalded or cooked
Microscopically
•Cells become swollen and their edges
become rounded
•cytoplasm stains slightly more intense
with eosin
•Internal structures of the cell are
slightly hazy
•Granular cytoplasm

5. Hydropicdegeneration
•It is a change closely related to cellular swelling in which cells take on clear
fluid to such an extend that they swell and may burst
•Uncomplicated hydropicdegeneration heals rapidly and leaves no scar or
permanent injury

6. Etiology
•More severe(1) mechanical injuries of a rubbing nature (skin of the hands of men
exposed to the friction from the shovel or axe handle, ill fitting shoes cause friction
of the foot and leads to blisters)
(2) Thermal injuries: both heat and cold
(3) Chemical injuries: croton oil, cantharidin, red iodide of mercury, and oil of mustard
in horses
(4) Infectious agents: viruses-pox viruses, FMD virus, vesicular exanthema of swine
(5) Neoplasms: cervix

7. Hydropicdegeneration
Macroscopically
•Seen as blister on the skin
•Upon incision, fluid escapes and
blister collapses
•If pyogenic bacteria –suppurative
inflammation
Microscopically
•Increase in size of the cell
•Small clear vacuoles may be seen
within the cytoplasm-vacuolar
degeneration
•Hydropicfluid stains pink with
eosin
•In skin-prickle cell layer

8. Mucinous or mucous degeneration
•Excessive accumulation of mucinin degenerating epithelial cells
•Mucin-a glassy, viscid, stringy, slimy glycoprotein, produced by columnar
and cuboidal epithelium
•Mucinmixed with water or tissue fluid-Mucus
•No permanent damage occurs

9. Etiology
•Occurs whenever a mild irritant is applied to a mucous membrane
•Mild mechanical injury
•Mild chemicals such as disinfectants and soap
•Irritating effect of moderate heat and cold
•Infectious agents-viral (canine distemper, bovine viral diarrhea)
•Neoplasms of columnar epithelium (adenocarcinoma)

10. Mucinous or mucous degeneration
Macroscopically
•Mucusmembraneiscoveredwithaclear,
whitetransparentmaterialwhichisstringy
andslimyinconsistency
•Eg.Viscousandwateryfluidfromhuman
noseduringcommoncold
•Mucusmembrane-hyperemic
•Largeamountofmucusisproducedinthe
genitaltractduringestrus-normal-
physiologicalmucus
Microscopically
•Mucinfirst appears in the cytoplasm of the
cell as small droplet
•As more droplet appear, they coalesce
forming larger droplets and displaces nucleus
to one side
•At last cell enlarges and ultimately ruptures
•Mucinstains blue with haematoxylinand red
with thionine, mucicarmineand periodic acid
Schiff staining

11. Mucoidor myxomatousdegeneration
•Appearance of glycoprotein similar to mucinin connective tissue which is
undergoing a disturbance in cell metabolism

12. Etiology
•Connective tissue cells in the foetusproduce mucinlike glycoprotein which is
not normally present in adult tissue and sometime this substance is found in
the adult in mucoiddegeneration
•Observed in connective tissue tumors-myxomasand myxosarcomas
•Myxoedema–a disease associated with thyroid deficiency in humans
•In cachectic animals observed in adipose tissue along the coronary band of
the heart, inter and intramuscular fat and in the mesenteric, omentaland
perirenalfats

13. Mucoidor myxomatousdegeneration
Macroscopically
•Tissue is shrunken, flaccid and
flabby in consistency and has a
translucent jelly like appearance
•When incised, a watery, slimy,
stringy material exudes from the
cut surface
Microscopically
•Degeneratingtissuestainsbluewith
hematoxylin,thenucleiare
hyperchromaticandthefluidinthe
intercellularspaceshasaslightly
bluishtinge

14. Pseudomucin
•It is the normal secretion of ovarian tissue and paraovariancysts, observed in
ovarian cystadenomasand cystadenocarcinomas
•Resembles mucinous degeneration and could mislead
•It is not precipitated by acetic acid while mucinis precipitated
•Stains pinkwith eosin instead of bluewith hematoxylinas does mucin
•Pseudomucinis not harmful since it is a normal cell secretion

15. Hyaline change
•Anyalterationwithincellsorintheextracellularspacewhichgivestissuea
homogenousglassytranslucentpinkappearanceinroutinehistological
sectionsstainedwithH&E
•Affectedcellsandtissueslosstheirstructuralcharacteristicsandfuse
togetherintoahomogenousmass
•Itisthephysicalappearanceoftissueratherthanitschemicalcomposition
thatdetermineswhetherhyalinedegenerationispresentornot

16. Hyalinis composed of protein of varying
composition and is of three major types:
•1. Keratohyalin
•2. Cellular hyaline
•3. Connective tissue hyalin

17. Keratohyalin
•Pathological:excessivemechanicalirritationoftheskinproducedbytheshoesor
bysaddlesorharnessesinthehorses
•Bytheactionofpapilloma(wart)virusincattleanddogs
•Hyperkeratosis(chlorinatednaphthalenepoisoning)incattle
•Squamouscellcarcinomainallspeciesofanimal,keratohyalinappearsintheform
ofepithelialpearls
•VitAdeficiencycausekeratinizationofepitheliuminthedigestiveandupper
respiratorytractsofthechicken

18. Cellular hyalin
•Occursincellsotherthanthosefoundinstratifiedsquamousepitheliumandconnectivetissue
•Cellsinmanyorgansaredesquamatedintoaglandularlumenorcavty-fuseintoahomogenous
massresemblingstarchorsand.Thesefirmmassesstaindeeplywithiodineandarecalledcorpora
amylacea(L.starchbodies)
•Observedinprostate-normal
•Alveolioflunginpneumoniaandpulmonaryinfarction
•Mammaryglandofcowsdriedofftooquickly
•Commonlyfoundintheventriclesofthebrainandcentralcanalofthespinalcord-Brainsand
•IsletsofLangerhansinindividualhavingdiabetics,plateletsinthrombi,cellsdesquamatedfrom
therenaltubularepitheliumwithalbuminformshyalinecasts

19. Connective tissue hyalin
•Observed in old scars, in the degenerating stromaof tumors, in the lymph
nodes draining areas of chronic inflammation, in the renal glomeruli in
chronic nephritis, and in the intima and media of blood vessels in
arteriosclerosis
•It is a permanent change