Dermatology - Benign Tumors and Premalignant Changes

From Iusmicm

Contents 1 Benign tumors 1.1 Seborrheic keratoses (SK) 1.2 Nevi 1.3 Cysts 2 Premalignant changes 2.1 Actinic keratoses

[edit] Benign tumors

[edit] Seborrheic keratoses (SK)

• Epidemiology of seborrheic keratosis:
  • the most common cutaneous neoplasm
  • unusual in children
  • increases in incidence with age (not-rare in children, very common in elderly)
  • no diff in gender

• Etiology of seborrheic keratosis: unknown

• Distribution:
  • any cutaneous surface but not the mucous membrane
  • primarily on the trunk (may have Christmas tree pattern)
  • The long axis of a seborrheic lesion is oriented along skin lines

• Appearance of seborrheic keratosis:
  • 1-2mm to 1-2cm in diameter
  • Yellow to dark brown
  • Macular or papular
  • Velvety or verrucous (thickened and scaly; wart-like) in texture
  • Stuck-on appearance
  • May appear greasy
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• Symptoms of seborrheic keratosis:
  • Usually asymptomatic
  • Occasionally pruritic
  • May become irritated if rubbed by a shirt, bra, collar, etc.

• Variants of sebhorreic keratosis:
  • Stucco keratoses: elderly; acral areas; 3-4 mm seborrheic keratoses; appear gray-white in color; asymptomatic
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  • Dermatosis papulosa nigra: in people with darker skin tones, on the face, multiple tiny seborrheic keratosis
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  • Note that stucco keratoses has large seborrheic keratoses while papulosa nigra has smaller seborrheic keratoses.

• Treatment
  • No treatment is generally needed; tx is initiated if irritated or for cosmetic reasons
  • Cryotherapy: freeze with liquid nitrogen
  • Electrosurgery: electrodesiccation for small lesions
  • Chemical peels: flattens and lightens the lesions
  • Laser: CO₂ or Erbium:Yag vaporizes the lesions

[edit] Nevi

• Nevi are benign proliferations nof melanocytes in the skin.

• Epidemiology of nevi:
  • Prevalence varies with age
  • Prevalence increases with lighter skin
  • Very common: 20x20: 20 nevi by 20yo in Caucasians

• Etiology of nevi:
  • Unknown
  • Nevi are probably related to cumulative UV light exposure
    • Painful sunburns before 20yo are associated with increased nevi development
    • Use sunscreen! It decreases new nevi in children
  • May have a genetic component

• Risk factors
• Distribution: any cutaneous surface
  • In kids, tends to be in sun-exposed areas

• Appearance:
  • Nevi are usually orderly: symmetrical, regular borders (round / oval), homogenous color, homogenous surface texture
  • Nevi come in several types: junctional, compound, or intradermal depending on their location in the epidermis / dermis
  • These types (junctional, compound, or intradermal) are used in pathologic descriptions and correlate with clinical appearance
    • Junctional nevi: nests of cells at the EDJ (epidermal-dermal junction); small (1mm - 1cm), round, flat (or slightly raised), light / dark brown / black
    • Compound nevi: nests of cells at the junction AND in the dermis; raised, papillomatous, skin-colored / light tan / brown / black
    • Dermal nevi: nests of cells are only in the dermis; raised (papules, may even be pedunculated or dome shaped), smooth or papillary surface, rubbery texture, flesh to brown
    • Type can change with normal life-cycle.
  • Note that compound nevi have the widest range of color.
  • Note that the deeper the nevus cells, the more raised the lesion: junctional nevi are flat or very slightly raised (at EDJ), compound nevi is (slightly) raised (at EDJ and dermis), dermal nevi are domed / pedunculated (at the dermis).
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• Pathogenesis (life cycle):
  • Nevi have a life cycle of appearance and regression
  • Nevi appear in months 6-12 of life
  • Nevi then increase in number and size in early childhood, puberty, and 2nd / 3rd decades
    • Recall that sun exposure increases risk
  • Nevi then regress later in life (eventually disappearing)
  • Nevi can have eruptive growth during adolescence, pregnancy, or with steroid / hGH use

• Diagnosis of nevi:
  • Family history of melanoma should be queried
  • Check the ABCDEs: asymmetry, (irregular) border, (jet-black or variegated) color, (increasing) diameter (or over 6mm; pencil eraser), (increasing) elevation
    • Also ask about itchiness, pain, or irritation
  • When in doubt, biopsy!: use a punch or excisional biopsy to get the best measurement of height from the granular cells.
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• Treatment of nevi:
  • Most require no treatment at all
  • Might excise for cosmetic reasons or if they become irritated

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• http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Histo%20Images/melanocytic_clark's_type_compound_nevus_high_power.jpg
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[edit] Cysts

• A cyst is any round to dome-shaped, mobile lesion that contains expressible material

What does "expressible mean"?

• Epidemiology of cysts:
  • Extremely common
  • Male:Female::2:1

• Etiology of cysts:
  • Usually idiopathic
  • May come from an occluded follicular infundibulum (section of hair follicle above the sebaceous gland)
  • May come from traumatically implanted epidermis as in surgical scars
  • May be a growth of skin-within-the-skin.

• Distribution of cysts: mainly the face (especially the preauricular area), neck, and chest
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• Appearance of cysts:
  • Usually flesh-colored papules or nodules (commonly dome-shaped)
  • 1-2mm to 1-2cm
  • Often has small central punctum connectin gthe cyst to the epidermis
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• Symptoms of cysts:
  • May become infected or inflammed

• Treatment:
  • Excision: surgery can be used to remove the cyst wall; recurrence if entirety of wall isn't removed
  • Manage complications (infected cysts): warm compresses (increases blood flow and immune access), incise and drain, antibiotics against skin flora (cloxacillin, erythromycin, cephalexin)
  • Be careful if the pt has heart valve infections because treatment of cysts may release pathogens into the blood and cause endocarditis.

[edit] Premalignant changes

[edit] Actinic keratoses

• Actinic keratosis is a pre-malignant lesion of keratinocytes

• Epidemiology of AK:
  • Usually occurs in fair-skinned individuals
  • Usually begins in 30s-40s
  • Elderly: 50%
  • Hot / sunny areas: 50%, younger onset (teens and 20s)
  • Develop over time

• Risk factors of actinic keratosis:
  • Fair skin
  • Older age
  • Blue eyes
  • Red or blond hair
  • Outdoor occupation or recreation
  • Childhood freckling

• Distribution: sun exposed areas
  • When on the mucosa (lips), called actinic cheilitis

• Appearance of actinic keratosis:
  • Color: flesh to erythematous
  • Ill-defined macule to papule: sometimes better felt than seen
  • Dry, adherent scaling
    • Sometimes better felt than seen
  • Size: pinhead diameter to several cm
  • Usually multiple lesions
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• Symptoms: usually asymptomatic

• Variants
  • Actinic cheilitis (lips)
    • Usually on the lower lips
    • Lesions have: scaling (diffuse and slight); commissures (sometimes over the entire lower lip); may show up as leukoplakia
    • Background skin has: blotchy, atrophic appearance; an indistinct and irregular vermillion with perpendicular wrinkles,

• Treatment of actinic keratosis:
  • AK can be treated with direct destruction or chemotherapy
  • Destructive modalities: liquid nitrogen, curettage, chemical peels, laser ablation
    • Curettage: physical scraping removal via curette
    • Chemical peel: chemical treatment that causes superficial layers to slough off
  • Chemotherapy: Topical 1-5% 5-fluorouracil; lights up subclinical lesions
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  • PDT: photodynamic therapy
    • Paint on a photosensitizer (chemical)
    • Pre-malignant cells uptake the chemical (more than other cells; takes several hours)
    • Hit with UV light to turn photosensitizer chemical into superoxide radicals
    • Death of pre-malignant cells