Derm E2: precancerous lesions

What is another name for actinic keratosis (AKs)?

solar keratosis

what are actinic keratosis (AKs)?

cutaneous lesion that results from proliferation of atypical epidermal keratinocytes; precursor lesion to SCC

What are clinical features of AKs?

classic type: erythematous, scaly macule, papule, or plaque w/ dry, rough appearance (most common)

hypertrophic type: thick adherent scale on erythematous base

atrophic type: scale is absent; lesions appear as smooth red macules

pigmented: hyperpigmented scaly macules or patches

actinic cheilitis: rough or scaly area on lip

AK w/ cutaneous horn: keratitis projection that resembles a cone

located on sun exposed areas

What is the pathophysiology of AKs?

excessive/cumulative UV exposure from sun → triggers pathological changes in epidermal keratinocytes by disrupting regulatory pathways in cell growth and differentiation

leads to inflammation and immunosuppression → proliferation of dysplastic keratinocytes

What are risk factors for AKs?

Fitzpatrick I-III

hx chronic sun exposure/sunburns

immunosuppression

HPV

age 20-70**

M > F

what type of AK is this?

classic (common) type

what type of AK is this?

hypertrophic

what type of AK is this?

AK w/ cutaneous horn

what type of AK is this?

actinic cheilitis

How do you dx AKs?

clinical; dermoscopy; skin bx if uncertain

histopathology: atypical keratinocytes limited to lower third of epidermis

When do you bx AKs?

painful, bleeding lesions; indurated; rapid recurring lesions

what is 1st line tx for AKs?

• topical 5-FU cream: preferred for flat lesions of face/scalp

• cryotherapy: preferred for multiple or resistant lesions

• curettage/shave: hyperkeratotic lesions resistant to topical tx

• surgical excision: preferred if high suspicion for SCC

what is 2nd line tx for AK?

• laser (CO2 and Erbium-YAG)

• chemical peels

• dermabrasion

When do you follow up for AKs?

ongoing monitoring for lesion recurrence 6-12 mos post tx

What are clinical features of a cutaneous horn?

• appearance of cone or horn w/ papular or radular base and keratitis cap

• SCC can be present at base

• other underlying lesions associated: viral warts due to HPV and AKs

Where are cutaneous horns located?

areas of dermatoheliosis (face, ear, dorsum of hands, forearms, shins)

How do you dx cutaneous horns?

excisional bx

What is the tx for cutaneous horns?

1st line: excisional bx

2nd line: CO2 laser

What is a keratoacanthoma (KA)?

rapidly growing epithelial tumor w/ potential for tissue destruction

(may be clinically indistinguishable from SCC)

what causes KAs?

arises from infundibulum of hair follicle due to genetic mutations

what are clinical features of keratoacanthomas (KAs)?

• sharply demarcated, firm, erythematous or skin colored dome shaped nodule w/ central keratotic plug

  • removal of keratotic core leaves a crater

• w/in few weeks , can grow to 1-2 cm

• spontaneous regression occurs w/in 2-6 mos in most cases

• location- sun exposed sites (esp. w/ hair)

what are risk factors for KAs?

age 50+

males

Fitzpatrick I-II

HPV

How do you dx KAs?

skin bx

What is tx for KAs?

1st line: surgical excision or Mohs surgery (for face lesions); only definitive way to distinguish from SCC

alt: electrodessication and curettage

What are congenital melanocytes nevi (CMN)?

hamartomas composed primarily of benign melanocytes during embryogenesis

present at birth and grows w/ child

what causes CMN?

localized genetic abnormalities causing proliferation of melanocytes

what area clinical features of CMNs?

• oval/round plaque w/ or w/o coarse terminal dark brown or black hair

• tend to extend deeper into dermis and SC tissue

• small: < 1.5 cm

• medium: 1.5-19.9 cm

• large: > 20 cm; typically have satellite lesions

• grows proportionally w/ child

How do you dx CMNs?

clinical; dermoscopy

How do you tx CMNs?

observation vs surgical excision; for small lesions, can wait until child is old enough to tolerate anesthesia

what are complications seen w/ large CMNs?

5-10% risk of malignant melanoma (70% are dx by 10 y/o)

what are clinical features of dysplastic / atypical nevi?

• precursor of malignant melanoma

• diameter > 5mm

• fried egg appearance- macular component w/ papular center

• asymmetry

• notched, irregular, ill-defined borders

• variegated color w/ areas of pink, tan, brown, dark brown

what are complications w/ dysplastic/atypical nevus?

malignant melanoma; 1 DN = 2x risk; 10+ DN = 12x risk

what are risk factors for DN?

fam hx of FAMM; genetic predisposition

How do you dx DN?

clinical; digitized dermoscopy

How do you manage DN?

• assess pt and lesion hx- focus on risk factors

• perform FBSE

• if lesion changing/suspicious → surgical excision

How do you prevent DN?

• sun protection

• skin checks x 3-12 mos depending on hx

  • if +FmHx melanoma or multiple DN → FU x 6 mos

• self skin exams