Pathology of the Skin Flashcards

1
Q

Macroscopic lesion:

Traumatic lesion breaking the epidermis and causing a raw linear area (i.e.: deep scratch); often self-induced

A

Excoriation

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2
Q

Macroscopic lesion:

Thickened, rough skin (similar to lichen growth on a rock); usually the result of repetitive rubbing

A

Lichenification

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3
Q

Macroscopic lesion:

Circumscribed flat lesion usually distinguished from surrounding skin by color, = 5 mm in diameter

A

Macule

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4
Q

Macroscopic lesion:

Circumscribed flat lesion usually distinguished from surrounding skin by color, > 5 mm in diameter

A

Patch

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5
Q

Macroscopic lesion:

Separation of nail plate from nail bed

A

Onycholysis

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6
Q

Macroscopic lesion:

Elevated dome-shaped or flat-topped lesion = 5 mm diameter

A

Papule

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7
Q

Macroscopic lesion:

Elevated dome-shaped lesion > 5 mm diameter

A

Nodule

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8
Q

Macroscopic lesion:

Elevated flat-topped lesion > 5 mm diameter; may be formed by coalescence of papules

A

Plaque

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9
Q

Macroscopic lesion:

Dry, horny, plate-like excrescence; usually the result of imperfect cornification

A

Scale

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10
Q

Macroscopic lesion:

General term of a fluid-filled raised lesion

A

Blister

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11
Q

Macroscopic lesion:

Fluid-filled raised lesion = 5 mm diameter

A

Vesicle

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12
Q

Macroscopic lesion:

Fluid-filled raised lesion > 5 mm diameter

A

Bulla

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13
Q

Macroscopic lesion:

Itchy, transient, elevated lesion with variable blanching and erythema formed as the result of dermal edema

A

Wheal

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14
Q

Microscopic lesion:

Diffuse epidermal hyperplasia

A

Acanthosis

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15
Q

Microscopic lesion:

Loss of intercellular connections between keratinocytes

A

Acantholysis

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16
Q

Microscopic lesion:

Abnormal, premature keratinization within cells below the stratum granulosum

A

Dyskeratosis

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17
Q

Microscopic lesion:

Focal discontinuity of the skin showing incomplete loss of the epidermis

A

Erosion

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18
Q

Microscopic lesion:

Infiltration of the epidermis by inflammatory cells

A

Exocytosis

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19
Q

Microscopic lesion:

Intracellular edema of kertinocytes, often seen in viral infections

A

Hydropic swelling/ballooning

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20
Q

Microscopic lesion:

Hyperplasia of the stratum granulosum, often due to intense rubbing

A

Hypergranulosis

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21
Q

Microscopic lesion:

Hyperplasia of the stratum corneum, often associated with a qualitative abnormality of keratin

A

Hyperkeratosis

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22
Q

Microscopic lesion:

A linear pattern of melanocyte proliferation within the basal cell layer

A

Lentiginous

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23
Q

Microscopic lesion:

Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae

A

Papillomatosis

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24
Q

Microscopic lesion:

Keratinization with retained nuclei in the stratum corneum (normal in mucous membranes)

A

Parakeratosis

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25
Q

Microscopic lesion:

Focal discontinuity of the skin showing complete loss of the epidermis, revealing dermis or subcutis

A

Ulceration

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26
Q

Microscopic lesion:

Intercellular edema of the epidermis

A

Spongiosis

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27
Q

Microscopic lesion:

Formation of vacuoles within or adjacent to cells; often refers to basal cell-basement membrane zone area

A

Vacuolization

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28
Q

Common nevus with the following description:

  • < 6 mm in diameter
  • uniformly pigmented
  • regular, well-defined
  • mostly in sun-exposed areas
  • no atypia, absent mitosis
  • no dermal reactions
  • RAS mutations (pro-growth signalling but intact tumor suppressant p16 prevents progression)
  • follows a maturation sequence
A

Melanocytic nevus

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29
Q

Common nevus with the following description:

  • > 5 mm in diameter
  • variegated pigments with pebbly surface
  • irregular borders, can be target-like with darker raised center and irregular flat periphery
  • found in both sun-exposed and non-sun-exposed areas
  • with lentiginous hyperplasia as nevus cells replace the normal basal cell layer along the dermo-epidermal junction
  • with atypia and mitosis
  • lymphocytic infiltration, linear fibrosis, and melanin incontinence
  • CDKN2A mutation (impaired tumor suppression activity), TERT (telomerase activation, prolonging cell life), RAS mutation (pro-growth signalling)
  • marker for melanoma risk
  • follows a turmor progression sequence
A

Dysplastic nevus

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30
Q

Syndrome of multiple (hundreds) of dysplastic nevi that is also a risk factor for melanoma

A

Dysplastic nevus syndrome

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31
Q

1st stage of melanocytic nevus MATURATION SEQUENCE:

  • nevus cells at the dermo-epidermal junction
  • growth pattern: nests
  • cells round, uniform, with inconspicuous nucleoli and no mitosis
  • tyrosinase-positive
  • cholinesterase-negative
A

Junctional nevus

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32
Q

2nd stage of melanocytic nevus MATURATION SEQUENCE:

  • nevus cells at the dermo-epidermal junction AND dermis
  • growth pattern: nests
  • cells round, uniform, with inconspicuous nucleoli and no mitosis
  • tyrosinase-positive
  • cholinesterase-negative
A

Compound nevus

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33
Q

3rd stage of melanocytic nevus MATURATION SEQUENCE:

  • nevus cells at the dermis
  • growth pattern: nests
  • cells round, uniform, with inconspicuous nucleoli and no mitosis
  • tyrosinase-positive
  • cholinesterase-negative
A

Intradermal nevus

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34
Q

4th stage of melanocytic nevus MATURATION SEQUENCE:

  • nevus cells at the dermis
  • growth pattern: fascicles
  • fusiform cells, spindle-shaped but non-dysplastic
  • tyrosinase-negative
  • cholinesterase-positive
A

Intradermal nevus with neurotization

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35
Q

Rate-limiting enzyme responsible for melanin regulation

A

Tyrosinase

Tyrosinase from melanocytes cleaves tyrosine, precursor to melanin and other pigments

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36
Q

1st stage of dysplastic nevus TUMOR PROGRESSION SEQUENCE:

  • involves the basal layer of the epidermis (dermo-epidermal junction)
  • no atypia and mitosis
A

Lentiginous junctional nevus

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37
Q

2nd stage of dysplastic nevus TUMOR PROGRESSION SEQUENCE:

  • involves the dermis and epidermis (with atypical cells in epidermis)
  • with atypia and mitosis
A

Lentiginous compound nevus

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38
Q

3rd stage of dysplastic nevus TUMOR PROGRESSION SEQUENCE:

  • involves the epidermis and superficial dermis
  • with atypia and mitosis
  • radial growth only
A

Early melanoma

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39
Q

4th stage of dysplastic nevus TUMOR PROGRESSION SEQUENCE:

  • involves the epidermis, dermis, and other structures
  • with atypia and mitosis
  • both radial and vertical growth
A

Advanced melanoma

40
Q

Specific type of early melanoma confined to the epidermis of sun-damaged skin

A

Lentigo maligna melanoma

41
Q

Specific type of melanoma with solely vertical growth (no radial growth)

A

Nodular melanoma

42
Q

Most common specific type of melanoma, known to spread over the lower extremities and back

A

Superficial spreading melanoma

43
Q

Specific type of melanoma confined to the sole, palm, or the areas beneath the nail; common in blacks

A

Acral melanoma

44
Q

A rare autosomal recessive genetic disorder of DNA repair in which the ability to repair damage caused by ultraviolet (UV) light (especially on the skin) is deficient; also a known risk factor for melanoma

A

Xeroderma pigmentosum (XP)

45
Q

5 clinical pearls of suspected melanoma

A
  • Asymmetry
  • Irregular borders
  • Variegated color
  • Increasing diameter
  • Evolution

(Mnemonic: ABCDE)

46
Q

Special diagnostic silver-based stain for melanoma, nevus cells

A

Melanin stains

47
Q

More specific immunostains used in the diagnosis of melanoma

A

S-100 and HMB-45

48
Q

Prognostic scale of melanoma based on the measurement of tumor depth

A

Breslow thickness (or Breslow’s depth)

49
Q

Benign epithelial tumor with the following characteristics:

  • hyperpigmented, coin-like, macular-to-raised, verrucoid lesions with stuck-on appearance
  • basaloid cells with variable pigment production
  • hyperkeratosis
  • horn cysts (keratin-filled cysts)
  • invagination cysts (invaginations of keratin)
A

Seborrheic keratosis

50
Q

Seborrheic keratoses presenting as multiple small facial lesions, commonly found in blacks

A

Dermatosis papulosa nigra

51
Q

Rapid increase in the number of seborrheic keratoses as a paraneoplastic syndrome of gastric adenocarcinoma and other GI cancers

A

Leser-Trelat sign

52
Q

Benign epithelial tumor with the following characteristics:

  • thickened, hyperpigmented skin with a velvet-like texture in flexural areas
  • cutaneous marker for benign conditions (DM, obesity) and some malignant conditions (GI cancers)
  • undulation of epidermis and dermal papillae
  • hyperkeratosis
  • basal cell hyperpigmentation without melanocytic hyperplasia
A

Acanthosis nigricans

53
Q

Premalignant epidermal tumor with the following characteristics:

  • found on sun-damaged skin
  • tan-brown, red, or skin-colored
  • rough, sandpaper-like
  • may have cutaneous horns (overproduction of keratin)
    cytologic atypia in basal epidermis with intercellular bridging
  • atypical basal cells with pink/reddish cytoplasm (dyskeratosis)
  • blue-gray basophilic degenerative changes in the elastic fibers (solar elastosis)
  • stratum corneum cells retain their nuclei (parakeratosis) with hyperkeratosis = “hyperparakeratosis”
A

Actinic keratosis

54
Q

Malignant epidermal tumor with the following characteristics:

  • second most common tumor arising in sun-exposed sites in older people
  • grossly as plaques, to nodules, to ulcers
  • mildly aggressive
  • commonly metastasizes
  • atypical SQUAMOUS cells involving full thickness of the epidermis with dermal invasion
  • keratin pearl formation
  • dyskeratosis
A

Squamous cell carcinoma (SCCA)

55
Q

Malignant epidermal tumor with the following characteristics:

  • most common invasive cancers in humans
  • grossly as pearly papules with telangiectasia, and ulceration
  • very aggressive
  • rarely metastasizes
  • nests of BASALOID cells (looks like the cells from the basal layer) with peripheral palisading
  • stromal retraction
A

Basal cell carcinoma

56
Q

Warty outgrowths caused by infection with human papillomavirus (HPV) 5 and 8, placing the patient in an immunosuppressed state, presenting as a major risk factor for SCCA

A

Epidermodysplasia verruciformis

57
Q

Inherited medical condition involving defects within multiple body systems such as the skin, nervous system, eyes, endocrine system, and bones - includes multiple nevoid BCCA

A

Gorlin syndrome (or Gorlin-Goltz syndrome)

58
Q

Characteristic large lesion of nodular BCCA that presents with central necrosis

A

Rodent ulcer (or Jacob’s ulcer)

59
Q

Inflammatory dermatosis with the following characteristics:

  • increased dermal microvascular permeability, presenting clinically as wheals
  • superficial dermal edema
  • sparse superficial perivenular mononuclear infiltrate
  • mast cell-mediated and IgE-mediated; type I hypersensitivity
  • mast cell-dependent; IgE-independent
A

Urticaria

60
Q

Urticarial involvement of the deeper dermis and subcutaneous fat

A

Angioedema

61
Q

Urticarial-like disorder that is BOTH mast cell and IgE-independent

A

Hereditary angioneurotic edema

62
Q

Characteristic pruritic edematous plaque of urticaria

A

Wheal

63
Q

Inflammatory dermatosis with the following characteristics:

  • red, papulovesicular, oozing, crusted lesions
  • raised, scaling plaques (reactive acanthosis and hyperkeratosis)
  • T cell-mediated; type IV hypersensitivity to contact antigens or internal circulating antigens (drugs)
  • CONTACT antigens cause SUPERFICIAL dermal perivascular MONONUCLEAR infiltrate
  • circulating/INTERNAL antigens cause both SUPERFICIAL and DEEP perivascular LYMPHOCYTIC infiltrate with EOSINOPHILS
  • hyperkeratosis, acanthosis, spongiosis
  • dermal edema may seep in to intracellular spaces of the stratum spinosum, causing intraepidermal vesicles
A

Acute eczematous dermatitis (or eczema)

(Forms:

  • allergic contact dermatitis
  • atopic dermatitis
  • drug-related eczematous dermatitis
  • photoeczematous dermatitis
  • primary irritant dermatitis)
64
Q

Inflammatory dermatosis with the following characteristics:

  • multiform and target lesions
  • interface dermatitis (lymphocytes at the dermo-epidermal junction associated with necrotic keratinocytes)
  • CD8+ T cell-mediated type IV hypersensitivity, associated with particular drugs, cancers, infections, and collagen vascular diseases
  • part of a spectrum encompassing SJS and TEN
A

Erythema multiforme

(Associated drugs:

  • sulfonamides
  • penicillins
  • barbiturates
  • salicylates
  • antimalarials
  • hydantoins

Associated infections:

  • HSV
  • Mycoplasma
  • histoplasmosis
  • Coccidiodes
  • salmonella
  • leprosy

Associated cancers:

  • carcinomas
  • lymphomas

Associated collagen vascular diseases:

  • SLE
  • polyarteritis nodosa (PAN)
  • dermatomyositis)
65
Q

Erythema multiforme spectrum involving < 10% total BSA, including mucosal involvement and systemic symptoms

A

Steven-Johnson syndrome (SJS)

66
Q

Erythema multiforme spectrum involving > 30% total BSA, with characteristic splitting of skin, formed by blisters occuring at the dermoepidermal junction

A

Toxic epidermal necrolysis (TEN)

Note: as opposed to staphylococcal SSS where splitting occurs at stratum granulosum due to bacterial toxin

67
Q

Erythema multiforme spectrum involving 10-30% total BSA

A

SJS-TEN overlap

68
Q

Inflammatory dermatosis with the following characteristics:

  • cell-mediated autoimmune dermatitis caused by CD4+ TH1, CD4+ TH17, and CD8+ accumulation in the epidermis
  • grossly with salmon-colored plaques covered by loosely adherent silvery-white scales usually seen on the sites of trauma
  • acanthosis with elongation of rete ridges (test tube rack appearance)
  • stratum granulosum thinned or absent with overlying parakeratotis (stratum corneum) scales
  • neutrophilic infiltrates in epidermis and within the parakeratotis stratum corneum
A

Psorias

69
Q

Clinical sign where lifting of the silvery-white scales in psoriasis causes pinpoint bleeding due to the dilated tortuous vessels in the dermal papillae

A

Auspitz sign

70
Q

Phenomenon in which psoriatic lesions tend to appear over areas of trauma - knees, elbows, scalp, lumbosacrum, intergluteal cleft, glans penis, etc.

A

Koebner phenomenon

71
Q

Histologic finding in psoriasis of acanthosis with significantly elongated rete ridges

A

Test tube appearance

72
Q

Inflammatory infiltrate in psoriasis, described as neutrophils in spongiotic foci of the superficial epidermis

A

Spongiform pustules of Kogoj

73
Q

Inflammatory infiltrate in psoriasis, described as neutrophils within the parakeratotic stratum corneum

A

Munro micro-abscesses

74
Q

Inflammatory dermatosis with the following characteristics:

  • high density of sebaceous glands
  • macules and papules on an erythematous-yellow, greasy base with extensive scaling and crusting
  • may be associated with Malassezia and/or immunosuppression
  • mounds of parakeratosis, with PMNs and serum at the ostia of hair follicles (FOLLICULAR LIPPING)
  • superficial perivascular inflammatory infiltrate (lymphocytes and neutrophils)
A

Seborrheic dermatitis

75
Q

Seborrheic dermatitis of the scalp

A

Dandruff

76
Q

Inflammatory dermatosis with the following characteristics:

  • pruritic, purple, polygonal, planar, papules and plaques (6 P’s)
  • white dots/lines on papules (WICKHAM STRIAE)
  • may be T cell-mediated
  • epidermal hyperplasia (or rarely atrophy), hyperkeratosis, hypergranulosis
  • interface dermatitis
  • SAWTOOTHING of the DEJ
  • Anucleate, necrotic basal cells in inflammed papillary dermis (CIVATTE BODIES or COLLOID BODIES)
A

Lichen planus

77
Q

Inflammatory blistering disease with the following characteristics:

  • targets desmoglein at the desmosomes
  • blisters located at the suprabasilar or subcorneal areas
  • involvement of mainly IgG antibodies
  • immunofluorescent at the intercellular squamous region (LACE-LIKE)
  • acantholysis
  • Nikolsksy sign-POSITIVE
A

Pemphigus

78
Q

The more common type of pemphigus where blisters are located at the suprabasilar level; may involve mucosal surfaces

A

Pemphigus vulgaris

79
Q

Less common type of pemphigus where blisters are located at the subcorneal level; endemic in Brazil; rarely involves mucosal surfaces

A

Pemphigus foliaceus

80
Q

Pemphigus associated with non-Hodgkin lymphoma

A

Paraneoplastic pemphigus

81
Q

Inflammatory blistering disease with the following characteristics:

  • antigens target hemidesmosomes
  • blisters located at subepidermal area
  • involvement of IgG antibodies
  • immunofluorescent at the epidermal basement membrane zone (LINEAR)
  • no acantholysis
  • basal cell layer vacuolization
  • Nikolsksy sign-NEGATIVE (tense bullae)
A

Bullous pemphigoid (or mucous membrane pemphigoid)

82
Q

The dislodgement of intact superficial epidermis by a shearing force, indicating a plane of cleavage in the skin - used to differentiate pemphigus (positive) from a bullous phemphigoid (negative)

A

Nikolsky sign (dermo-epidermal separation)

83
Q

Inflammatory blistering disease with the following characteristics:

  • antigens target reticulin (fibrils that anchor the epidermis to the superficial dermis)
  • blisters located at subepidermal area
  • involvement of IgA antibodies
  • immunofluorescent at the epidermal basement membrane zone (GRANULAR)
  • fibrin and PMNs at the tips of dermal papillae
  • associated with celiac disease
A

Dermatitis herpetiformis

84
Q

Non-inflammatory blistering disease with the following characteristics:

  • defects in either keratin, laminin & BPAGs, or type VII collagen
A

Epidermolysis bullosa (EB)

85
Q

Type of epidermolysis bullosa associated with defects in keratin (most common)

A

EB simplex

86
Q

Type of epidermolysis bullosa associated with defects in laminin and bullous pemphigoid antigens (BPAGs)

A

Junctional EB

87
Q

Type of epidermolysis bullosa associated with defects in type VII collagen (anchoring collagen)

A

Dystrophic EB

88
Q

Non-inflammatory blistering disease with the following characteristics:

  • inherited defects in heme metabolism
  • accumulation of porphyrins in the skin
  • sun-induced skin damage
A

Porphyria

89
Q

Disorder of epidermal appendage with the following characteristics:

  • chronic inflammation of the pilosebaceous unit
  • histological hallmark: comedones (comedogenesis)
  • keratin plug leads to sebaceous gland hypertrophy and the proliferation of Propionibacterium acne (lipase-synthesizing baction), leading to a secondary inflammation
  • universal in the middle-to-late teenage years
  • may be further precipitated by drugs (corticosteroids, ACTH, testosterone, gonadotropins, OCPs, trimethadione, iodides), occupational exposures (cutting oils, chlorinated hydrocarbons, coal tar), occlusive conditions (heavy clothing, cosmetics), and tropical climates
A

Acne vulgaris

90
Q

Lesion of acne comedogenesis involving a small follicular papule with central black plug due to melanin oxidation

A

Open comedone (or the “blackhead”)

91
Q

Lesion of acne comedogenesis involving small follicular papule without any visible plug; keratin plug beneath epidermal surface

A

Closed comedone (or the “whitehead”)

92
Q

Skin infection caused by HPV:

  • gray-white to tan papules, flat-to-convex with pebbly surface
  • undulating papillomatous epidermal hyperplasia
  • koilocytic atypia (cytoplasmic vacuolization seen as a perinuclear halo)
A

Verruca

93
Q

Skin infection caused by poxvirus:

  • pruritic, pink to skin-colored papules with central umbilication
  • large, ellipsoid, homogenous cytoplasmic inclusions in the stratum granulosum and stratum corneun (MOLLUSCUM BODIES)
A

Molluscum contagiosum

94
Q

Skin infection caused by either Group A beta-hemolytic streptococci (Streptococus pyogenes) or Staphylococcus aureus:

  • honey-colored crusts
  • accumulation of neutrophils beneath the stratum corneum
A

Impetigo

95
Q

Impetigo caused by Streptococcus pyogenes (GABHS)

A

Impetigo contagiosa

96
Q

Impetigo caused by Staphylococcus aureus

A

Impetigo bullosa