MORPHOLOGIC LESIONS

1. RAISED LESIONa. Papule

= a solid, elevated lesion less than 0,5 cm in size which a significant projects above the plane of the surrounding skin. Oblique lighting with a flashlight in a darkened room is often necessary to detect slight elevation. Papules with scaling are referred to as

papulosquamous lesions. Sessile, pedunculated, dome-shaped, flat topped, rough, smooth, filiform, mammillated, acuminate, and umbilicated constitute some common shapes and surfaces of papules. Clinical shape : lichen planus

b. Plaque

= a solid plateau-like elevation that occupies a relatively large surface area in comparison with its height above the normal skin level and has a diameter larger than 0,5 cm. Plaques may form by extension/confluence of papules. Clinical shape : psoriasis

c. Nodule

= nodule is a palpable, solid, round or ellipsoidal lesion. Depth of involvement and/or substantive palpability, rather than diameter, differentiate a nodule from a papule. Depending upon the anatomic component(s) primarily involved, nodules are of five main types: (1) epidermal, (2) epidermal-dermal, (3) dermal, (4) dermal-subdermal, and (5) subcutaneous. Clinical example : Basal Cell CarcinomaTumor the heading of nodule, mass, benign/malignantGumma granulomatous nodule lesion of tertiary syphilis

d. Cyst

= an encapsulated cavity/sac lined with a true epithelium that contains fluid or semisolid material (cells and keratin). Cyst may be hard, doughy, or fluctuant. Clinical example : Cystic Hidradenoma

e. Wheal

= a swealing of the skin that is characteristically evanescent, disappearing within hours. Also known as hives, urticaria edema produced by the escape of plasma through vessel walls in the upper portion of the dermis. Wheals may be tiny papules 2-4mm or giant papules greater than 10mm. Wheals can be seen as an allergic response to innumerable initiating agents, such as drugs and insect bites. Wheal-like lesions occur occasionally in dermatitis herpetiformis and bullous pemphigoid. The wheal produced in response to the stroking of a reddish-brown or brownish macule (Darier's sign) is pathognomonic of urticaria pigmentosa (mastocytosis). Stroking of the skin may produce wheals in some normal persons; this phenomenon is called dermographism, classified as one of the physical urticarias.

f. Scar

= arises from proliferation of fibrous tissue that replaces previously normal collagen after a wound or ulceration breaches the reticular dermis. Deeper pink to red color early in before hypo/hyperpigmented. Hypertrophic scars firm papules, plaques, nodules. Keloid scars elevated. Atrophic scars depressed plaques.

g. Comedo

= hair follicle infundibulum that is dilated and plugged by keratin and lipids. Pilosebaceous inits open the surface of the skin with a visible keratinaceous plug open comedo. The black color oxidized sebaceous content of the infundibulum

(blackhead). Closed infundibulum in which the folliculalr opening is unapparent accumulates whitish keratin closed comedo. Clinical example : comedomal acne

h. Horn

= a conical mass cornified cells arising over an abnormally differentiating epidermis. HPV replication in keratinocytes of a wart or the clonal expansion of mutated keratinocytes in squamous cell carcinoma. Clinical example : verruca vulgaris

i. Calcinosis

= deposits of calcium in the dermis or subcutaneous tissue may be appreciated as hard, whitish nodules or plaques, with or without visible alteration of the skin’s surface. Clinical example : cutaneous calcinosis in dermatomyositis

2. DEPRESSED LESIONa. Erosion

= a moist, circumscribed, depressed lesion that results from loss of a portion or all of the viable epidermal or mucosal epithelium. Clinical example : TEN

b. Ulcers

= a defect in which the epidermis and at least upper (papillary dermis) has been removed. Clinical example : pyoderma gangrenosum

c. Atrophy

= a diminution iin the size of a cell, tissue, organ, or part of the body. Decrease number of epidermal cells thinning of the epidermis.

d. Poikiloderma

= combination of atrophy, telangiectasis, and varied pigmentary change over an area of the skin. Clinical example : chronic radiodermatitis

e. Sinus

= a tract connecting deep suppurative cavities to each other or to the surface of the skin. Contents of the cabity : pus, fluid, keratin, drain to the surface. Clinical example : hidradenitis suppurativa

f. Striae

= linear depressions of the skin that usually measure several centimeters in length and result from changes to the reticular collagen that occur with rapid stretching of the skin. Clinical example : striae distensae

g. Burrow

= wavy, threadlike tunnel through the outer portion of the epidermis excavated by a parasite, few millimeters in length. Clinical example : scabetic burrow

h. Sclerosis

= circumscribed or diffuse hardening or induration in the skin that is a result of dermalfibrosis. Clinical example : morphea

3. FLAT LESIONa. Macule

= flat lesion, even with the surface level of surrounding skin, perceptible as an area of color different from the surrounding skin or mucous membrane. Clinical example : lentigo

b. Erythema

= blancable change in color of skin or mucous membrane that is due to dilatation of arteries and veins in the papillary and reticular dermis. Clinical example : fixed drug eruption

c. Patch= similar to macule, flat area of skin or mucous membrane with a different color from its surrounding. Clinical example : vitiligo

d. Erythroderma

= generalized deep redness of the skin involving more than 90 percent of the body surface within days to weeks. Clinical example : sezary syndrome

4. SURFACE CHANGEa. Scale, Desquamation (Scaling)

= flat plate or flake arising from the outer most layer of the stratum corneum. Clinical example : psoriasis vulgaris

b. Crusts (encrusted exudates)

= hardened deposits that results when serum, blood, or purulent exudate dries on the surface of the skin. Clinical example : impetigo

c. Excoriations

= surface excavations of epidermis that results from scratching and are frequent finding in patients experiencing pruritus.

d. Fissure

= a linear loss continuity of the skin’s surface or mucosa that results from excessive tension or decreased elasticity of the involved tissue. Clinical example : fissure on the palm associated with contact dermatitis

e. Lichenification

= repeated rubbing of the skin may induce a reactive thickening of the epidermis, with changes in the collagen of the underlying superficial dermis. Clinical example : LSC

f. Keratoderma

= excessibe hyperkeratosis of the stratum corneum that results in a yellowish thickening of the skin usally on the palms or soles that may be inherited (abnormal

keratin formation) or acquired (mechanical stimulation). Clinical example : plantar keratoderma

g. Eschar

= tissue necrosis, infacrction, deep burns, gangrene, or other ulcerating process. Clinical example : thermal burn

5. FLUID FILLEDa. Vesicle and Bulla

- Vesicle : fluid filled cavity or elevation smaller than or equal to 0,5 cm. clinical example : toxin producing staphylococcal impetigo

- Bulla (blister) : measures larger than 0,5 cm. clinical example : a bullous pemphigoid

b. Pustule

= a circumscribed, raised cavity in the epidermis or infundibulum containing pus. Clinical example : superficial pyoderma

c. Furuncle

= a deep necrotizing folliculitis with suppuration. Several furncle may coalesce to form a carbuncle.

d. Abscess

= a localized accumulation of purulent material so deep in the dermis or subcutaneous tissue that the pus is usually not visible on the surface of the skin. Clinical example : folliculitis resulting from streptococcal or staphylococcal infection

6. VASCULARa. Purpura

= extravasation of blood from cutaneous vessles into skin/mucous membrane results in reddish purple lesions. Diascopy differentiate between erythema and purpura. Redness is non-blanching under the

pressure of the slide purpuric lesion. Clinical example : leukocytoclastic vasculitis.

b. Telangiectasia

= persistent dilatations of small capillaries in the superficial dermis that are visible as fine, bright, non pulsatile red lines or net like patterns on skin not disappear with diascopy.

c. Infarct

= area of cutaneous necrosis resulting from a bland or inflammatory occlusion of blood vessels in the skin. Tender, irregularly shaped dusky reddish fray macule or firm plaque that is sometimes depressed slightly below the plane of the skin. Clinical example : cholesterol emboli