The Skin Flashcards
Disease of depigmentation secondary to destruction of melanocytes.
Vitilligo
Disease of depigmentation secondary to decreased or absent synthesis of melanin.
Albinism
These are nevi, usually <6 mm, benign-looking, clinically and histologically, and are removed for cosmetic reasons; these lesions have RAS mutations but most never progress because of intact p16 (tumor-suppressor) activity.
Melanocytic nevus
These are large nevi (>5 mm) and may occur as hundreds of lesions on the body surface; they are flat macules to slightly raised plaques, with a “pebbly” surface; considered as a marker of melanoma risk.
Dysplastic nevi
The most deadly of all skin cancers; results from excessive sun exposure; malignant cells have large nuclei with irregular contours having chromatin characteristically clumped at the periphery of the nuclear membrane and prominent eosinophilic nucleoli often described as “cherry red”; has both radial and vertical growth phases.
Melanoma
Immunohistochemical staining for melanoma.
S-100, and HMB-45 (more specific)
Clinically mimics melanoma; round, exophytic, coin-like plaques varying in diameter, with a velvety/granular surface; tan to dark brown in color; it has a stuck-on appearance often seen in older individuals; the lesions consist of an orderly proliferation of uniform, monotonous sheets of small cells (basaloid in appearance) with a tendency to form keratin microcysts (horn cysts).
Seborrheic keratosis
This lesion is usually the result of chronic exposure to sunlight; dermis contains thickened, blue-gray elastic fibers or “solar elastosis” which is the result of chronic sun damage; grossly, lesions are less than 1cm, tan-brown or red in color, with sandpaper-like surface; microscopically, there is Atypical dyskeratotic cells in basal epidermis with intercellular bridges, solar elastosis, hyperparakeratosis and dermal chronic inflammation.
Actinic keratosis
A common tumor arising on sun-exposed sites in older people, with higher incidence in women; may arise from prior actinic keratoses, then when advanced becomes nodular and may ulcerate; characterized by anaplastic (seen on all levels of the epidermis), rounded cells with foci of necrosis and only abortive, single-cell keratinization (dyskeratosis).
Squamous cell carcinoma
This is the most common human cancer, which is a slow-growing tumor that rarely metastasizes; tends to occur at sites subject to chronic sun exposure and in lightly pigmented people; These tumors present as pearly, smooth-surfaced papules, often containing prominent, dilated subepidermal blood vessels (telangiectasia); the cells have scant cytoplasm, small hyperchromatic nuclei, and a peripheral palisade with clefting from the stroma.
Basal cell carcinoma
Condition caused by local mast cell degranulation; histologically, there is usually a sparse superficial perivenular infiltrate of mononuclear cells with superficial dermal edema.
Urticaria
This term is the accumulation of edema fluid within the epidermis; characterizes all forms of eczamatous dermatitis.
Spongiosis
An uncommon, usually self-limited disorder that seems to be a hypersensitivity response to certain infections and drugs; patients present with an array of “multiform” lesions, including macules, papules, vesicles, and bullae, as well as the characteristic targetoid lesion consisting of a red macule or papule with a pale vesicular or eroded center; part of a spectrum with SJS-TEN.
Erytherma multiforme
A skin disorder whose main pathology is increased epithelial cell turnover; there is acanthosis and loss of the stratum granulosum with extensive overlying parakeratotic scale; there is also a regular downward elongation of rete ridges (test tubes in a rack appearance); associated with multiple punctate hemorrhages upon removal of scales from the lesions (Auspitz sign) due to presence of dilated tortuous vessels.
Psoriasis
Small aggregates of neutrophils within the parakeratotic stratum corneum (Munro microabscesses); and spongiotic superficial epidermis (Pustules of Kogoj) are findings associated with:
Psoriasis
