BASIC PATHOLOGY OF THE SKIN
BASIC PATHOLOGY OF THE SKIN
By:Ma. Carmen L. Cagampan,
M.D.,F.P.S.P.
ANATOMY AND HISTOLOGY OF THE SKINANATOMY AND HISTOLOGY OF THE SKIN
I. EPIDERMIS A. Different Layers:
1. Stratum Basalis2. Stratum Spinosum3. Stratum Granulosum*4. Stratum Corneum
*filled with keratohyaline granules (keratogenous zone)
Stratum Malpighii(nucleated portion)
ANATOMY AND HISTOLOGY OF THE SKINANATOMY AND HISTOLOGY OF THE SKIN
B. Special cells of the EPIDERMIS1. Melanocytes dispersed in the basal cell layer increases when exposed to sunlight
2. Merkel cells found in the basal cell layer of skin, oral mucosa
and hair follicle touch receptor
3. Langerhan’s cells found in suprabasal epidermis have Ag presenting capacity (related to
monocytes/macrophages)
Melanocyte
ANATOMY AND HISTOLOGY OF THE SKINANATOMY AND HISTOLOGY OF THE SKIN
C. Epidermal Appendages1. Hair follicle2. Sebaceous glands3. Eccrine glands4. Apocrine glands5. Nails
ANATOMY AND HISTOLOGY OF THE SKINANATOMY AND HISTOLOGY OF THE SKIN
II. DERMIS
Dermal Microvascular UnitVessels, nerves, migrant inflammatory cells
Dermal Muscles cells
Dermal Fibroblasts
Dermal Lymphatics
Extracellular Matrix
III. SUBCUTANOEUS TISSUE
PROPERTIES OF THE SKINPROPERTIES OF THE SKIN
1. Maintains integrity of the body2. Protects from injurious stimuli3. Absorbs and excretes liquids4. Regulates temperature5. Water proofs6. Absorbs ultraviolet light7. Metabolized vitamin D8. Detects sensory stimuli9. Provides cosmetic function
10. Acts as barrier against microorganisms
MACROSCOPIC TERMS USED IN DERMATOLOGYMACROSCOPIC TERMS
USED IN DERMATOLOGY1. MACULE
– circumscribed lesion of up to 5mm* in diameter characterized by flatness and usually distinguished from surrounding skin by its coloration
– e.g. vitiligo, freckles
* Some sources use 10mm as the size boundary between different lesions
MaculeMacule
Circumscribed lesion of more than 5mm in diameter characterized by flatness and usually distinguished from surrounding skin by its coloration.
PatchPatch
3. PAPULE
elevated dome-shaped or flat –topped lesion < 5 mm across
e.g. warts, nevi, dermal tumor, acne vulgaris
4. NODULEelevated lesion with spherical contour > 5 mm acrosse.g. EIC, keratoacanthoma, appendage tumor
Nodule
5. PLAQUEElevated flat-topped area, usually > 5 mm acrosse.g. psoriasis, seborrheic keratosis, mycosis fungoides
Plaque
6. VESICLE
Fluid-filled raised area < 5mm
e.g. herpes zoster, chicken pox, eczematous dermatitis
7. BULLA
fluid-filled raised area >5 mm across
e.g. pemphigus
MACROSCOPIC TERMS USED IN
DERMATOLOGY
MACROSCOPIC TERMS USED IN
DERMATOLOGY
8. BLISTER Common term used for vesicle or bulla
9. PUSTULE
discrete, pus-filled, raised area
e.g. impetigo, acne vulgaris
Pustule
10. WHEAL
Itchy, transient, elevated areas with variable blanching and erythema formed as a result of dermal edema
e.g. urticaria, insect bites
Wheal
11. SCALE
dry, horny, platelike excrescenses
e.g. psoriasis, tinea infection (capitis, corpora)
Scale
12. LICHENIFICATION
thickened and rough skin characterized by prominent skin markings
e.g. lichen simplex, eczematous dermatitis
Lichenification
13. EXCORIATION
traumatic lesion characterized by breakage of the epidermis
e.g. body louse infestation
Excoriation
14. ONYCHOLYSIS
loss of integrity of nail substance
e.g. psoriasis
Onycholysis
MICROSCOPIC TERMS USED IN
DERMATOPATHOLOGY
MICROSCOPIC TERMS USED IN
DERMATOPATHOLOGY1. HYPERKERATOSIS
– Hyperplasia / thickening of the stratum corneum
– e.g. psoriasis, squamous cell carcinoma
Hyperkeratosis
2. PARAKERATOSIS– mode of keratinization characterized by the
retention of the nuclei in the stratum corneum– e.g. psoriasis
Parakeratosis
3. HYPERGRANULOSIS
-Hyperplasia of the stratum granulosum
4. ACANTHOSIS– epidermal
hyperplasia– e.g. verucca
vulgaris
5. DYSKERATOSIS– abnormal keratinization occurring prematurely
within individual cells – e.g. actininc keratosis, squamous cell carcinoma
6. ACANTHOLYSIS– loss of intercellular connections resulting in
loss of cohesion between keratinocytes– e.g. pemphigus vulgaris (primary), impetigo
Acantholysis
Acantholysis
7. PAPILLOMATOSIS– hyperplasia of the papillary dermis
verruca vulgaris
Papillomatosis
8. LENTIGINOUS– refers to the linear pattern of melanocyte
proliferation within the epidermal basal cell layer– e.g. lentigo simplex
Lentiginous
9. SPONGIOSIS– intercellular edema of the epidermis– e.g. acute eczematous dermatitis
Spongiosis
Spongiosis
10. HYDROPIC SWELLING– Intracellular edema of keratinocytes– Often seen in viral infections
11. EXOCYTOSIS
infiltration of the epidermis by inflammatory or circulating blood cellse.g. Inflammatory dematoses, mycosis fungoides
Exocytosis
Exocytosis
12. EROSION discontinuity of the skin exhibiting incomplete
loss of the epidermis
13. ULCERATION– discontinuity of the skin exhibiting complete
loss of the epidermis– e.g. basal cell CA, squamous cell CA
Ulceration
Ulceration
14. VACUOLIZATION
formation of vacuoles within or adjacent to cells
e.g. koilocytosis in verruca vulgaris, basal cell vacuolation in L.E.
Vacuolization