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