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Toronto Notes 2019 Pre-Malignant Skin Conditions Pre-Malignant Skin Conditions
Actinic Keratosis (Solar Keratosis)
Clinical Presentation
• ill-defined,scaly,erythematouspapulesorplaquesonabackgroundofsun-damagedskin(solarheliosis)
• sandpaper-like,grittysensationfeltonpalpation,ofteneasiertoappreciateonpalpationratherthan
inspection
• sites:areasofsunexposure(face,ears,scalpifbald,neck,sun-exposedlimbs)
Pathophysiology
• UVradiationdamagetokeratinocytesfromrepeatedsunexposure(especiallyUVB)
• riskoftransformationofAKtoSCC(~1/1,000),buthigherlikelihoodifAKispersistent
• UV-inducedp53genemutation
• riskfactors:increasedage,lightskin/eyes/hair,immunosuppression,syndromessuchasalbinismor
xeroderma pigmenotsum
• risk factors for malignancy: immunosuppression, history of skin cancer, persistence of the AK
Epidemiology
• commonwithincreasingage,outdooroccupation,M>F
• skinphototypesI-III,rareindarkerskinasmelaninisprotective
Differential Diagnosis
• SCCinsitu,superficialBCC,seborrheickeratosis,cutaneouslupuserythematosus Investigations
• biopsylesionsthatarerefractorytotreatment
Management
• destructive:cryotherapy,electrodessication,andcurettage
• topicalpharmacotherapy(mechanism:destructionofrapidlygrowingcellsorimmunesystem
modulation)
■ topical 5-Fluorouracil cream (for 2-4 wk), Imiquimod 5% (2x/wk for 16 wk), Imiquimod 3.75%
(daily for 2 wk then none for 2 wk then daily for 2 wk), Ingenol Mebutate gel 0.015% (daily for 3 d
on the head and neck), Ingenol mebutate 0.05% gel (daily for 2 d on the body)
• photodynamictherapy
• excision
Leukoplakia
Clinical Presentation
• amorphologictermdescribinghomogeneousorspeckledwhiteplaqueswithsharplydemarcated borders
• sites:oropharynx,mostoftenfloorofthemouth,softpalate,andventral/lateralsurfacesofthetongue
Pathophysiology
• precancerousorpremalignantcondition
• oralformisstronglyassociatedwithtobaccouseandalcoholconsumption
Epidemiology
• 1-5%prevalenceinadultpopulationafter30yrofage;peakatage50 • M>F,fair-skinned
• mostcommonoralmucosalpremalignantlesion
Differential Diagnosis
• lichenplanus,oralhairyleukoplakia,whitespongenevus
Investigations
• biopsyismandatoryduetoriskofmalignancy
Management
• lowrisksitesonbuccal/labialmucosalorhardpalate:eliminatecarcinogenichabits,smokingcessation, follow-up
• moderate/dysplasticlesions:excision,cryotherapy
Dermatology D33
Types of AK
• Erythematous: typical AK lesion
• Hypertrophic: thicker, rough papule/plaque • Cutaneous horn: firm hyperkeratotic
outgrowth
• Actinic cheilitis: confluent AKs on the lip • Pigmented: flat, tan-brown, scaly plaque • Spreading pigmented
• Proliferative
• Conjunctival: pinguecula, pterygium