Dermatopathology

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Dermatopathology

• The study of diseases that affect the skin.

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A, The skin is composed of an epidermal layer (e)
from which specialized adnexa (hair follicles, h
sweat glands, g and sebaceous glands, s) descend
into the underlying dermis (d). B, This
projection of the epidermal layer (e) and
underlying superficial dermis demonstrates the
progressive upward maturation of basal cells (b)
into cornified squamous epithelial cells of the
stratum corneum (sc). Melanin-containing
dendritic melanocytes (m) (and rare Merkel cells
containing neurosecretory granules) and
midepidermal dendritic Langerhans cells (lc) are
also present. The underlying dermis contains
small vessels (v), fibroblasts (f), perivascular
mast cells (mc), and dendrocytes (dc),
potentially important in dermal immunity and
repair.
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Macroscopic Terms

• Macule flat, circumscribed, distinguished by
  color
• Papule elevation lt5 mm
• Nodule elevation gt5 mm
• Plaque flat-topped elevation gt5 mm
• Vesicle fluid-filled blister lt5 mm
• Bulla fluid-filled blister gt5 mm
• Pustule discrete, pus-filled area
• Scale dry, horny, plate-like excrescence
• Lichenification thickened rough skin with
  prominent markings

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Microscopic Terms

• Hyperkeratosis increased keratin
• Parakeratosis keratinization with retention of
  nuclei
• Orthokeratosis keratinization without retention
  of nuclei
• Acanthosis epidermal hyperplasia
• Dyskeratosis abnormal premature keritinization
• Acantholysis loss of keratinocyte cohesion
• Papillomatosis hyperplasia of papillary dermis
• Lentiginous linear proliferation of melanocytes
  in epidermal basal layer
• Spongiosis intracellular edema of epidermis

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Acute Inflammatory Dermatoses

• Urticaria
• Acute eczematous dermatitis
• Erythema multiforme

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Urticaria

• Dermal microvascular hyperpermeablity that
  results in the formation of pruritic, edematous
  plaques (wheals).

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Urticaria

• Ages 20-40
• Small, pruritic papules/large edematous plaques
• Individual lesions of short duration although
  episodes may last days-months
• IgE mediated antigen induced or angioedema

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Urticaria
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Eczema

• A clinical term for any number of skin diseases
  characterized by red, papulovesicular, oozing,
  and crusted lesions which evolve into scaling
  plaques.

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Evolution of plaques in eczema
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Eczematous Dermatitis

• Contact dermatitis
• Atopic dermatitis
• Drug-related eczematous dermatitis
• Photoeczematous eruption
• Primary irritant dermatitis

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Vitiligo
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Eczematous Dermatitis
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Contact dermatitis (hair colorant)
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Drug-related Eczematous Dermatitis (Penicillin)
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Irritant dermatitis (lip licking and sucking)
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Erythema Multiforme

• Self-limiting hypersensitivity response to
  infectious agents or drugs (by cytotoxic T cells).

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Erythema Multiforme Associated Conditions

• Infections HSV, Mycoplasma, histoplasmosis,
  typhoid, leprosy, coccidioidomycosis
• Drugs sulfonamides, penicillin, barbiturates,
  salicylates, hydantoins, antimalarials
• Cancers carcinomas lymphoma
• Autoimmune diseases dermatomyositis, SLE,
  polyarteritis nodosa

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Erythema Multiforme

• Sudden onset of macules, papules, vesicles,
  bullae target lesions
• Skin, mucous membranes, conjunctiva, urethra,
  anogenital region
• Usually self-limiting but Stevens-Johnson
  syndrome and toxic epidermal necrolysis variants
  can be severe and life-threatening

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Erythema multiforme

• Typical sloughing oral lesion Typical target
  skin lesion

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Erythema multiforme with genital lesion
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Erythema multiforme with conjunctivitis in
Stevens Johnson syndrome
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Erythema multiforme toxic epidermal necrolysis
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Chronic Inflammatory Dermatoses

• Psoriasis
• Lichen Planus

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Psoriasis

• Affects 1-2 in USA chronic, familial
• Sometimes associated with arthritis, myopathy,
  enteropathy, AIDS
• Well-demarcated pink/salmon plaques covered by
  silver-white scales on elbows, knees, scalp,
  lumbosacral, intergluteal cleft, glans penis 50
  nail dystrophy
• T cell infiltration with cytokine growth factor
  release rapid epidermal turnover
• Auspitz sign Munro abscesses
• UV therapy

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Lichen Planus

• Idiopathic, mucocutaneous, self-limiting in 1-2
  years
• Skin lesions are pruritic, purple, polygonal
  papules extensor of arms, flexor or legs,
  Wickham striae
• Post-inflammatory hyperpigmentation
• Oral lesions more common reticulated

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Lichen planus
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Lichen planus
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Oral Lichen planus
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Blistering (Vesiculobullous)Diseases

• Pemphigus
• Bullous pemphigoid
• Cicatricial pemphigoid (BMMP)
• Dermatitis herpetiformis

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Blisters
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Pemphigus

• Autoimmune attack on desmoglein 3, the
  intercellular cementing substance by an IgG
  autoantibody
• Most middle-aged progressive vulgaris type can
  be fatal if untreated 1-5/1,000,000
• Vulgaris vegetans, foliaceus and erythematosus
  subtypes
• Affects skin (scalp, face, groin, axilla, trunk)
  mucous membranes
• Suprabasal acantholytic blister
• Positive Nikolsky sign

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Pemphigus vulgaris
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Histopatholgy of pemphigus
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Positive immunofluorescence (fish-net pattern) to
desmoglein 3 indicative of pemphigus
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Skin lesions in pemphigus vulgaris
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Oral lesions pemphigus vulgaris
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Bullous Pemphigoid

• Autoimmune attack of the basal lamina zone
  hemidesmosome
• Tense bullae thighs, flexor forearms, axillae,
  groin, lower abdomen oral involvement 8-39
• Older adults 10/1,000,000 positive Nikolsky
  sign tends to be limited

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Bullous pemphigoid
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Bullous pemphigoid
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Positive immunofluorescence along basal lamina
(candy ribbion pattern) indicative of bullous
pemphigoid
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Bullous or cicatricial pemphigoid --
subepithelial blister
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Cicatricial Pemphigoid

• Autoimmune attack on BLZ more common than
  pemphigus
• Oral lesion are most common may have
  conjuctival, nasal, esophageal, laryngeal,
  vaginal lesions
• Also known as benign mucous membrane pemphigoid
• 21 females age 50-60 Nikolsky sign tends to
  be progressive

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Oral lesions of cicatricial pemphigoid
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Ocular lesions in cicatricial pemphigoid
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Dermatitis Herpetiformis

• Rare autoimmune (IgA-autoantibodies localized in
  tips of dermal papillae)
• Urticaria with closely grouped vesicles pruritic
  rash elbows, knees, upper back, buttocks
• Age 20-30 celiac disease
• Responds to gluten-free diet

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Deratitis herpetiformis
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Dermatitis/stomatitis herpetiformis
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Skin Tumors

• Benign and premalignant epithelial lesions
• Malignant epidermal tumors
• Tumors and tumor-like lesions of melanocytes

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Seborrheic Keratosis

• Common benign epidermal tumor middle aged older
• Round, flat, coin-like plaques, tan to brown
  (stuck-on) multiple on trunk, extremities,
  head, neck
• May mimic melanoma dermatosis papulosa nigra
  internal malignancy paraneoplastic syndrome
  (Leser-Trélat sign)

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Seborrheic keratosis/dermatosis papulosa nigra
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Keratoacanthoma

• Rapidly developing, benign tumor, mimics squamous
  cell carcinoma rarely but occasionally found on
  vermilion of lower lip
• Sun-damaged skin males aged 50
• Biopsy/excision self-healing

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Keratoacantoma
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Keratoacanthoma of lip
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Verrucae (warts)

• Self-limiting epidermal tumors caused by HPV
• Any age but most common in children/adolescents
• Grey to tan papules with rough pebble-like
  surface, flat or cauliflower-like mass
• Verruca vulgaris / verruca plantatis Dorsum of
  hands, periungual, palm/sole, face rare
  intraoral
• Genital wartscondyloma acuminatum

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Verruca vulgaris
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Verruca vulgaris
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Actinic Keratosis

• Increased keratosis associated with dysplasia
  (premalignancy)
• Tan-brown, red or normal sand-paper-like lesion
  on sun-damaged skin cutaneous-horn

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Actinic keratosis (cutaneous horn)
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Actinic cheilitis (actinic keratosis of the lip)
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Squamous Cell Carcinoma(Epidermoid Carcinoma)

• 2nd most common skin cancer, arising in skin that
  is sun-damaged
• Other factors include topic or ingested
  carcinogens, ulcers, burns, fistulae
• More common in mengtwomen, mean age near 70
• 90 5-year cure rate ?5 metastasize

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Squamous cell carcinoma of skin
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Squamous cell carcinoma of the lip
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Squamous cell carcinomas of the lip
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Oral squamous cell carcinoma
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Basal Cell Carcinoma

• Most common cancer in man
• 75 of all skin cancers
• Damage of sun-exposed skin immunosuppression
• Slow growth, metastasis rare locally destructive
• Metastasis lt0.1 90 5-year cure rate 20-30
  additional lesion(s) within one year

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Basal cell carcinoma
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Basal cell carcinoma
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Basal cell carcinoma middle-third of face
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Basal cell carcinoma of lip
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Basal cell carcinoma -- pigmented and morphea
variants
Pigmented?
Pigmented?
Morphea ?
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Advanced basal cell carcinoma
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Nevocellular Nevus

• Congenital or acquired neoplasm of melanocytes
• Tan/brown, uniformly colored, lt5 mm, papules with
  well-defined rounded borders
• Maturation decreased lack junctional activity,
  cords of smaller cells with little pigment

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Nevocellular nevi
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Dysplastic Nevi

• Occur sporadically or familial
• Larger, numerous, flat or pebbly, variegation,
  irregular borders
• Both sun-exposed and non-sun areas of skin
• Lentigenous hyperplasia and enlarged
  intraepidermal nests of melanocytes
• Hereditary form at very high risk of melanoma

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Dysplastic nevi melanoma in situ
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Malignant Melanoma

• Cutaneous melanoma associated with sun damage or
  dysplastic nevi
• CDKN2A mutation common (cyclin-dependent kinase
  inhibitor)
• Itching, variegation, enlargement, irregular
  borders, new mole
• Radial/vertical growth dictates behavior
• Metastasis to lymph nodes, liver, lungs brain

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Melanoma of skin
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Mucosal (oral) melanoma
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Mucosal (oral) amelanotic melanoma
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Intraocular Melanoma

• Only 1/20th as frequent as cutaneous melanoma
• Uvea (iris) or retina
• Spindle celllow aggressiveness 75 15-year
  survival
• Epitheliod typeaggressive 35 15- year survival

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Ocular melanoma