A Primer on Skin Cancers
Cathryn Zhang, MD
University of Arizona
3/8/14
Objectives
1.
2.
3.
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
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
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: 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
◦ 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