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1. Skin Pathology

2. THE SKIN
• largest and heaviest organ, Account for 15-20 % of body weight
• Has various functions :
1. Physical barrier
2. Homeostasis
3. Sensorial organ
4. Immunology
5. cosmetics

3. Varies according to body region
• Composed of
I. Epidermis
II. Dermis
III. Subcutis(hypodermis)
IV. Skin appendage

4. Epidermis
• Stratified squamous keratinized epithelium
• Composed of four types of cells
I. Keratinocytes
II. Melanocytes
III. Langerhan cells
IV. Merkel cells

5. Keratinocytes
Keratinocyte:constitute 90-95 % of
epidermal cell
• Produce keratin
• Stratified into five orderly layer
I. Stratum Basalis
II. Stratum spinosum
III. Stratum granulosum
IV. Stratum lucidum
V. Stratum cornuem

6. Disease of stratum basale
• Basal cell carcinoma
• Graft vs host disease
• Erythema multiforme

7. Basal cell carcinoma
• Most common human cancer, UV exposure single most important risk
factor
• These are slow-growing tumors that rarely metastasize. The vast majority
are recognized at an early stage and cured by local excision.
• The syndrome in question, nevoid basal cell carcinoma syndrome
(NBCCS) (also known
as Gorlin syndrome), is an autosomal dominant disorder characterized by
the development of multiple basal cell carcinomas.

8. Tumor composed of nest basaloid cell infiltrating fibrous stroma. The cell
resemble basal cell have palisading nucleas with scanty cytoplasm and
small hyperchromatic nuclei.

10. Stratum spinosum
• The thickest layer epidermis
• Polyhedral cells with round oval nucleus,
prominent nucleoli and cytoplasm
• Stratum spinosum is thicker at area
subjected to pressure and friction like sole
of foot and palms
• The cell in this layer bound together by
desmosome

11. Disease of stratum spinosum
• Squamous cell carcinoma
• Pemphigus vulgaris

12. Squamous cell carcinoma
• 2nd most common human cancer. UV light is single most important risk
factor
• Can be squamous cell carcinoma insitu or invasive squamous cell
carcinoma.
• A second common association is with immunosuppression.
• Other risk factors include industrial carcinogens, chronic ulcers and
draining
osteomyelitis, old burn scars, tobacco and betel nut chewing

14. Pemphigus
• Pemphigus is a blistering disorder caused by autoantibodies
that result in the dissolution of intercellular attachments within
the epidermis and mucosal epithelium.
• The majority of individuals who develop pemphigus are in the
fourth to sixth decades of life.
• There are multiple variants: (1) pemphigus vulgaris (2)
pemphigus vegetans, (3) pemphigus foliaceus (4) pemphigus
erythematosus, and (5) paraneoplastic pemphigus

15. Pemphigus vulgaris
• Auto-immune disease ,Commonly old age.
• Most affected patient have oropharnygeal involment.
• Primary lesions are superficial vesicles and bullae that rupture
easily.

16. Stratum granulosum
• 3-5 flattened polygonal
cell wich Accumulate
keratohyaline granule
• Granule contain
cysteine
• Finally keratin fills cells
and destroy organelles
to produce stratum

17. Stratum lucidum
• Found only in thick skin.
• Translucent ,thin flattened
eosinophilic layer of epidermis
• No organelle and nucleus
• Packed with dense keratin and
desmosome may be present
between cells.

18. Stratum
corneum
• Consist of 15-20 cell
layer of nonnucleated
Keratinized cell.
• Cytoplasmic
organelle absent may
due to lysosomal
hydrolytic enzyme

19. The melanocyte
• 2nd most populous cells
• Constant number in all human race
• Found at basal layer, hair follicle, the
dermis
• Smaller than keratinocytes
• Posses thin dendritic cytoplasmic
process, extend to stratum spinosum

20. Melanocyte cont…
• Has elongated oval nucleus
surrounded by clear space
• synthesize melanin in organnel
called melanosomes using
tyrosinase enzyme.
• Melanin pigment Transferred
from melanocyte to keratinocyte
by phagocytosis.

21. Disease melanocyte
• Vitiligo
• Albinisim
• Melanocytic nevus
• Dysplastic nevi
• melanoma

33. Melanoma
• Most notorious skin
cancer
• Single most
important risk factor
UV exposure
• ABCDE’S of
melanoma