9. Spongiosis:
Intercellular edema of the
epidermis
Lentiginous hyperplasia
A linear pattern of melanocyte
proliferation within the epidermal
basal cell layer
12.
generally:
Acute inflammatory lesions characterized by:
Last from days to weeks.
Inflammatory infiltrates usually composed of lymphocytes and
macrophages rather than neutrophils.
Edema& variable degrees of epidermal, vascular, or
subcutaneous injury.
Chronic inflammatory lesions:
Persist for months to years.
Associated with changes in epidermal growth (atrophy or
hyperplasia) or dermal fibrosis.
The skin surface is roughened as a result of excessive or
abnormal scale formation and shedding.
13. Urticaria (hives)
Is a common disorder of the skin characterized by
localized mast cell degranulation and resultant dermal
microvascular hyperpermeability → pruritic edematous
plaques called wheals.
Age:
20-40 years. although all age groups are susceptible.
Sites
Any area exposed to pressure, such as the trunk, distal
extremities & ears.
14. 1)
1)
Pathogenesis.
Urticaria results from antigen-induced release of
vasoactive mediators from mast cell granules through
sensitization with specific IgE antibodies.
IgE-dependent reaction:
Pollens, foods, drugs, insect venom
IgE-independent urticaria:
Opiates, certain antibiotics, curare, and radiographic contrast,
aspirin
3) Complement-mediated urticaria :
Hereditary angioneurotic edema
15. Lesion:
Vary from small, pruritic
papules to large
edematous plaques
individual lesions may
coalesce to form annular,
linear, or arciform
configurations.
17. Eczema(dermatitis)
Meaning “to boil over.
Inflammatory response to a
variety of agents acting on
the skin from outside or from
within the body
Lesion:
Red, papulovesicular, oozing,
and crusted lesions and
become progressively scaly
plaqus.
18.
Initial dermal edema and
perivascular infiltration by
inflammatory cells.
is followed by epidermal spongiosis
& microvesicle formation .
Abnormal scale, including
parakeratosis, follows, along with
progressive acanthosis and
hyperkeratosis.
20. Psoriasis
Psoriasis is a common chronic inflammatory dermatosis
affecting as many as 1% to 2% of people .
Age:
all ages.
Site:
skin of the elbows, knees, scalp, lumbosacral areas,
intergluteal cleft and glans penis.
21. •
lesion:
Is a well-demarcated,
pink to salmon-colored
plaque covered by
loosely adherent scale
that is characteristically
silver-white in color
22. 1)
2)
3)
4)
5)
Microscopic:
Acanthosis with regular downward elongation of the rete
ridges appearing like test tubes in a rack .
Elongation and edema of the dermal papillae with
broadening of their tips.
The stratum granulosum is thinned or absent.
Prominent parakeratosis.
Presence of Munro micro abscesses in the parakeratotic
(Auspitz sign).
Blood vessels in the dermis rupture when scales are picked off
25. Verrucae (warts)
Def.:
Verrucae are common viral lesions of the skin.
Causes:
Human papilloma viruses.
Transmission:
Direct contact between individuals or auto-inoculation.
Verrucae are generally self-limited, regressing
spontaneously within 6 months to 2 years.
26. Types:
1) Verruca vulgaris
2) Verruca plana (flat wart) :
HPV-10.
Occurs in the face or dorsal surfaces of the hands
3) Verruca palmaris :
HPV-1
occurs on the soles and palms
4) Condyloma acuminatum (venereal wart) :
HPV-6.
Occurs on the penis, female genitalia
27. Verruca vulgaris
The most common type of wart.
Causes:
HPV-1 & 2.
Site:
More commonly on the dorsal surfaces of hands and
fingers.
28. Grossly
Number:
Multiple
Size :
Less than 1 cm .
Shape:
Papules .
Surface:
Rough , pebble-like surface.
Site: commonly on the dorsal
surfaces of hands and fingers.
.
Color: Gray-white to tan.
29. Microscopic:
1) Hyperkaratosis.
2) Parakeratosis.
3) Acanthosis.
4) Elongation of rete ridges.
5) Papillomatosis (Papillary folds).
6) Superficial epidermal cells contain prominent vacuolation
(koilocytosis).
These cells on electron microscopy reveal numerous
intranuclear viral particles.
30.
31. Impetigo
A common superficial bacterial infection of skin. It is highly
contagious.
Age:
Healthy children
Adults in poor health.
Causes:
Group A β-hemolytic streptococci → impetigo contagiosa
Staphylococcus aureus → impetigo bullosa
Site:
Usually involves exposed skin, particularly that of the face
and hands.
33.
Microscopic:
The characteristic feature is the subcorneal pustule which
is a collection of neutrophils under the stratum corneum.
Often, a few acantholytic cells and gram-positive bacteria
are found within the pustule.
The upper dermis contains severe inflammatory reaction
composed of neutrophils and lymphoid cells.
Rupture of pustules → superficial layering of serum,
neutrophils and cellular debris to form the characteristic
crust.
39. Grossly
Shape: They are sharply-
demarcated, It often protrudes
above the skin surface so it
appears ‘stuck on’ the skin(coin
like).
Surface: a coarsely granular.
Size: a few millimeters.
Color: tan to dark brown.
40. •
•
Microscopic features:
Pathognomonic feature is a
sharply demarcated
exophytic growth pattern with
many keratin-filled ‘horn
cysts .
The other features are
papillomatosis,
hyperkeratosis and
acanthosis’
47. Lesion:
1) Sharply defined, red, scaling
plaques.
2) More advanced, invasive
lesions are nodular, show
variable keratin production
(appreciated grossly as
hyperkeratotic scale), and may
ulcerate
49. Microscopic feature:
Well differentiation:
the dermis or submucosa is
infiltrated by groups of malignant
epithelial cells which in well
differentiated neoplasm form cell
nests.
the periphery of these shows basal
cells differentiated followed by
prickle cells , then granular cells
with center of the nests showing
keratins.
50.
51. High differentiated:
Cell nests are absent in
and the malignant cells
show more marked
anaplasia
Spread: direct ,lymphatic
and by blood.
54.
Def.:
Locally malignant(no-metastasize, slow growth) tumor arising
from basal cell of epidermis.
Age:
elderly age common related to chronic sun exposure
Site:
Common location (90%) being the face, usually above a
line from the lobe of the ear to the corner of the mouth.
57. Gross
Tumor start as slightly shiny
red papule or nodules
gradually enlarged and
ulcerated called ‘rodent
ulcer’
Character of ulcer;
Shape :irregular
Edge: raised rolled in
beaded edge
Floor: rough
Base: firm
58.
59. •
•
•
Microscopic:
The dermis is invaded by basophilic clusters of columnar
basal cells (basaloid cells) with characteristic peripheral
palisaded appearance while the central cells are
polyhedral.
The clusters of tumor cells are separated from dermal
collagen by a space called shrinkage artifact.
Spread: only local no distant spread.
