Dermatopathology Flashcards
Excoriation
Traumatic lesion breaking the epidermis and causing a raw linear area (i.e., deep scratch); often self-induced
Lichenification
Thickened and rough skin characterized by prominent skin markings (as lichen on a tree trunk); usually the result of repeated rubbing
Macule
Circumscribed lesion, 5 mm or smaller in diameter, characterized by flatness and distinguished by coloration (patch is greater than 5 mm)
Onycholysis
Separation of nail plate from nail bed
Papule
Elevated dome-shaped or flat-topped lesion 5 mm or less across (nodule is greater than 5 mm)
Plaque
Elevated flat-topped lesion, usually greater than 5 mm across (may be caused by coalescent papules)
Pustule
Discrete, pus-filled, raised lesion
Scale
Dry, horny, platelike excrescence; usually the result of imperfect cornification
Vesicle
Fluid-filled raised lesion 5 mm or less across (Bulla is greater than 5 mm. Blister is the common term for either.)
Wheal
Itchy, transient, elevated lesion with variable blanching and erythema formed as the result of dermal edema
Acantholysis
-Loss of intercellular cohesion between keratinocytes
Acanthosis
Diffuse epidermal hyperplasia
Increased spinosum
Dyskeratosis
Abnormal, premature keratinization within cells below the stratum granulosum
Erosion
Discontinuity of the skin showing incomplete loss of the epidermis
Exocytosis
Infiltration of the epidermis by inflammatory cells
Hydropic swelling (ballooning)
Intracellular edema of keratinocytes, often seen in viral infections
Hypergranulosis
Hyperplasia of the stratum granulosum, often due to intense rubbing
Hyperkeratosis
Thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin
Lentiginous
A linear pattern of melanocyte proliferation within the epidermal basal cell layer
Papillomatosis
Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae
Parakeratosis
Keratinization with retained nuclei in the stratum corneum. On mucous membranes, parakeratosis is normal.
Spongiosis
Intercellular edema of the epidermis
Ulceration
Discontinuity of the skin showing complete loss of the epidermis revealing dermis or subcutis
Vacuolization
Formation of vacuoles within or adjacent to cells; often refers to basal cell-basement membrane zone area
Poison Ivy
- Acute Allergic contact dermatitis
- pruitic vesticulobullous eruption
- Micro: spongiosis, intre-epidermal vesicles
- Inflammatory infiltrate in upper dermis
- Caused by Poison Ivy, poison oak, poison sumack: rxn to haptan
- Delayed type hypersensitivity: CD4 Th1 cells respond to antigens and secrete inflammatory cytokines
Pemphigus vulgaris
- blistering disorder
- autoantibodies to desmoglein of desmosomes
- dissolution of intercellular attachments within the epidermis and mucosal epithelium,
- oral ulcers that may persist for months before skin involvemen
- superficial vesicles and bullae that rupture easily, leaving shallow erosions covered with dried serum and crust
- pustules on the groin, axillae, and flexural surfaces.
- acantholysis, the dissolution, or lysis, of the intercellular adhesions that connect squamous epithelial cells
- Keratinocytes become rounded
- Basal keratinocytes remain attacked while others separate: “row of tombstones”
- Positive Nikolsky’s sign
Erythema Multiforme
- hypersensitivity reaction to certain infections and drugs
- herpes simplex, mycoplasmal infections, histoplasmosis,
- sulfonamides, penicillin, barbiturates, salicylates
- Typical lesion is erythematous papule w/ central vesicle giving a target appearance
- Multiple subepidermal blisters w/ dermal edema
- Mononuclear dermal infiltrate w/ necrotic keratinocytes
- More severe forms: Steven Johnson’s and TENS
Psoriasis
-Common chronic inflammatory dermatosis
-Red papules & plaques covered by white adherent scales
- most frequently affects the skin of the elbows, knees, scalp, lumbosacral areas, intergluteal cleft, and glans penis.
- Nail changes occur in 30% of cases of psoriasis: pitting, dimpling, separation of the nail plate, or thickening
-pustular psoriasis multiple small pustules form on erythematous plaques.
-acanthosis, with regular downward elongation of the rete ridges
-The stratum granulosum is thinned or absent, and extensive overlying parakeratotic scale is seen
-hinning of the portion of the epidermal cell layer that overlies the tips of dermal papillae
-dilated, tortuous blood vessels within these papillae.
-Koebner’s sign: trauma causes it to occur there
Awwswuts: removing plaqe causes bleading
Seborrheic keratoses
- common epidermal tumors in middle-aged or older individuals
- numerous on the trunk, although the extremities, head, and neck
- appear as round, flat, coin-like, waxy plaques that vary in diameter
- uniformly tan to dark brown and usually have a velvety to granular surface.
- Histology: hyperkeratosis acanthosis, papillomatosis, melanocytic hyperplasia and horn cysts
- mutations in the fibroblast growth factor receptor-3 (FGFR3) gene are found in many sporadic seborrheic keratoses
- part of a paraneoplastic syndrome (Leser-Trélat sign), possibly under the stimulation of transforming growth factor-α
Bullous Pemphigoid
- Autoimmune disorder w/ antibodies agains hemidesmosomes
- Attach the epidermal basment membrane
- Eosinophils in tense blisters
- Less severe than pemphigus vulgaris: spares oral mucosa
- NEGATIVE nikolsky’s sign
Dermatitis Herpetiformis
- Itchy pruritic papules and vesicles
- Often on elbows, knees, back, and butt
- Deposits of IgA at tips of dermal papillae
- Associated w/ celiac disease
Lichen Planus
-Puritic, purple, polygonal, papules
-Sawtooth infiltrate of lymphocytes at dermal-epidermal junction
-Associated w/ HepC
Also in mouth
Actinic Keratosis
- Premalignant lesions caused by sun exposure
- Small, rough, erythematous or brownish papules
- Cutaneous horn
- Risk of carcinoma proportional to epithelial dysplasia
Acanthosis nigricans
- Hyperplasia of stratum spinosum
- Associated w/ hyperinsulinemia (Cushing’s or diabetes) & visceral malignancy
- brown to black, poorly defined, velvety hyperpigmentation
- usually in body folds: neck, the axilla, groin, umbilicus, forehead
Erythema nodosum
- Inflammatory lesions of subcutaneous fat
- Usually on anterior shins
- Associated w/ coccidiomycosis, histoplasmosis, TB, leprosy, strep, and sarcoidosis
Squamous Cell Carcinoma
- Common. Associated w/ excessive sun or arsenic exposure
- Commonly on hands or face
- locally invasive but rarely metastasize
- Ulcerative red lesions
- Associated w/ chronic draining sinuses
- Histology: keratin pearls
- invasive tongue
- Actinic keratosis is precursor to squamous cell carcinoma
- Keratoacanthoma is variant that grows rapidly and regresses spontaneously
- Positive for H&E test
Basal Cell Carcinoma
- Most common in sun exposed ares of body
- Locally invasive, by almost never metastasizes
- Rolled edges under central ulceration
- pearly papules commonly w/ telangiectasis
- Palisading nuclei
- -Negative for all 3 tests
Melanoma
- Common tumor w/ significant risk of metastasis
- Associated w/ sun exposure: fair skin increased risk
- Depth of tumor correlates w/ risk of metastasis
- ABCD: asymmetry, border irregularity, color variation, diameter
