A Primer on Skin Cancers Cathryn Zhang, MD University of Arizona 3/8/14

Outline / Plan Pictures: Visual Dx, expert consult Time permitting: ◦ Prevention – sun protection ◦ Genetic syndromes that increase risk of skin cancer. ◦ Other risk factors, e.g. radiation, arsenic, immunosuppression.

Objectives 1. Review the major types of skin cancers (basal cell carcinoma, squamous cell carcinoma, melanoma) 2. Describe the treatment options for skin cancers 3. 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

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: % ◦ Lymph node most common ◦ Lung, bone, distant skin, liver, pleura Rare cause for mortality: 0.12/100,000 ( %)

Treatments Mohs micrographic surgery Excision ED&C (electrodessication and curettage) Cryotherapy Topical (superficial subtype only) ◦ Imiquimod ◦ Fluorouracil XRT Photodynamic therapy Vismodegib: smoothened inhibitor

Excision vs Mohs

Treatments Mohs micrographic surgery Excision ED&C (electrodessication and curettage) Cryotherapy Topical (superficial subtype only) ◦ Imiquimod ◦ Fluorouracil XRT Photodynamic therapy Vismodegib: smoothened inhibitor

ED&C

Treatments Mohs micrographic surgery Excision ED&C (electrodessication and curettage) Cryotherapy Topical (superficial subtype only) ◦ Imiquimod ◦ Fluorouracil XRT Photodynamic therapy Vismodegib: smoothened inhibitor

SQUAMOUS CELL CARCINOMA

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: % 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 ◦ Dx histopathologically 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