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A Primer on Skin Cancers. Cathryn Zhang, MD University of Arizona 3/8/14. Objectives. Review the major types of skin cancers (basal cell carcinoma, squamous cell carcinoma, melanoma) Describe the treatment options for skin cancers
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A Primer on Skin Cancers Cathryn Zhang, MD University of Arizona 3/8/14
Objectives • Review the major types of skin cancers (basal cell carcinoma, squamous cell carcinoma, melanoma) • Describe the treatment options for skin cancers • Recognize the risk of skin cancers arising in chronic wounds (specifically SCCs, termed Marjolin's ulcer)
Skin Cancer Disease Burden • Very common, especially in individuals with fair complexion • Estimated annual cases: 3.5 million • 1 in 5 Americans will develop skin cancer in their lifetime • Amount of annual UV radiation correlates with incidence
National Cancer Institute stats More than 3.5 million nonmelanoma skin cancers are diagnosed annually.
Types of skin cancers • BCC: 2.8 million cases annually • SCC: 700,000 cases annually • Melanoma: 76,690 cases in 2013 • Other types comprise < 1% of skin cancers: cutaneous lymphomas (CTCL, CBCL and all their variants), leukemia cutis, Merkel cell carcinoma, DFSP, AFX, Kaposi’s sarcoma, angiosarcoma, liposarcoma, Paget’s disease, EMPD, MAC, clear cell sarcoma, pilomatrix carcinoma, sebaceous carcinoma, adenoid cystic carcinoma, eccrine porocarcinoma, mucinous carcinoma, hidradenocarcinoma, eccrine ductal carcinoma, apocrine carcinoma, superficial malignant fibrous histiocytoma, epithelioid sarcoma, malignant peripheral nerve sheath tumor, leiomyosarcoma, cutaneous metastases, etc.
Basal cell carcinoma • Basaloid cells which appear similar to cells in the basal layer of the epidermis • Thought to arise from pluripotent stem cells within hair follicles • Types: • Nodular: up to 80% • Superficial • Morpheaform • Fibroepithelial • Arises in sun-damaged skin • Can ulcerate • Occasionally can be pigmented
Nodular BCC • Most common subtype • Primary lesion • Shiny, pearly papule or nodule • Smooth surface • Arborizing telangiectasias • Ulcerate with enlargement ,“rodent ulcer” • Face (cheeks, melolabial folds, forehead, eyelids), any hair-bearing area of skin
Superficial BCC • Well-circumscribed, erythematous macule/patch or thin papule/plaque • Few mm to several cm • Focal scale and/or crust • Thin rolled border • Spontaneous regression in larger lesions • Favors trunk and extremities
Morpheaform BCC • Less common aggressive subtype • Primary lesion • Slightly elevated or depressed indurated light pink to white patch/plaque • Ill-defined borders • Resembles scar • Smooth +/- crusts, erosions, ulcerations • +/- telangiectasia • Absence of rolled border
Fibroepithelial BCC (Fibroepithelioma of Pinkus) • Skin-colored or pink pedunculated papulonodule with smooth surface • Can resemble acrochordon or an intradermal nevus • Favors trunk (lower back)
Prognosis • Usually slow growing with local extension • Metastases extremely rare: 0.0028-0.55% • Lymph node most common • Lung, bone, distant skin, liver, pleura • Rare cause for mortality: 0.12/100,000 (0.00012%)
Treatments • Mohs micrographic surgery • Excision • ED&C (electrodessication and curettage) • Cryotherapy • Topical (superficial subtype only) • Imiquimod • Fluorouracil • XRT • Photodynamic therapy • Vismodegib: smoothened inhibitor
Treatments • Mohs micrographic surgery • Excision • ED&C (electrodessication and curettage) • Cryotherapy • Topical (superficial subtype only) • Imiquimod • Fluorouracil • XRT • Photodynamic therapy • Vismodegib: smoothened inhibitor
Treatments • Mohs micrographic surgery • Excision • ED&C (electrodessication and curettage) • Cryotherapy • Topical (superficial subtype only) • Imiquimod • Fluorouracil • XRT • Photodynamic therapy • Vismodegib: smoothened inhibitor
Actinic keratosis (AK)Syn: solar keratosis, senile keratosis • Pre-cancerous • Atypical keratinocytes in the basal layer of the epidermis (not full-thickness) • No risk of metastasis • Evolution to SCC: 0.075-0.096% per lesion per year estimated 5% chance of developing SCC over 5-10 years.
Actinic Keratosis • Clinical features • Present on sun-damaged skin • Head, neck, upper trunk and extensor extremities • Cluster in areas of highest sun exposure • Superior helices of ears • Upper forehead • Supraorbital ridge • Nasal bridge • Malar eminences • Dorsal hands • Extensor forearms • Bald scalp
Actinic Keratosis • Clinical features • Primary lesion • Rough erythematous papule with white to yellow scale • +/- tenderness • Few mm to confluent patches several cm • Early sign: slight erythema with imperceptible scale • Clues: background photodamage (dyspigmentation, telangiectasia, wrinkling) • Advanced lesion: thicker, better defined
Actinic Keratosis Variants • Hyperkeratotic/hypertrophic • Papules, plaques with scale or scale-crust on an erythematous base • Base extends beyond overlying hyperkeratosis • Pigmented AK • Usually lacks erythema • Hyperpigmented/reticulated appearance
Actinic Keratosis Variants • Lichenoid AK • Dxhistopathologically by dense, band-like inflammatory infiltrate • More erythema than traditional AK • Atrophic • Minimal surface change • Pink/red slightly scaly macule or patch • Actinic cheilitis • Lower vermilion lip • Classic vs diffuse • +/- leukoplakia
Treatments • Cryotherapy: >99% • Topical therapies: • Fluorouracil: 50% have 100% clearance • Imiquimod: 50% have 100% clearance • Diclofenac: 40% clearance • Ingenol mebutate: 34-47% clearance rate • Retinoids: mixed results • Photodynamic therapy: 50-70% clearance • Surgical: Shave removal or curettage
AKs • Consider removal: • pearly or glassy appearance • palpable dermal component • > 6mm • persistence after multiple treatments