Diagnosis
Malignant?
Comments
Junctional nevi
No
Dark, flat, smooth lesions. They are occasionally hairy and develop from the basal layer of epidermis. Nevi that are located on the palms and soles are usually junctional. They are benign lesions with a very low risk of malignant degeneration. Most common mole of children,
Compound nevi
No
Brown to black, well-circumscribed lesions that are < 1 cm in diameter. They may be elevated and are frequently hairy, arising from the epidermal-dermal interface and from within the dermis. Malignant transformation is rare.
Intradermal nevi
No
Light-colored, well-circumscribed lesions < 1 cm in diameter. Hairs are usually present and the cell distribution occurs in the dermis. Malignant transformation is rare. Most common mole in adults.
Giant pigmented nevi
No
Brown to black hairy lesions with an irregular nodular surface. They are frequently described as a bathing trunk type of lesion. Malignant degeneration occurs in about 10 %. Excision is recommended.
Spitz nevi
No
Smooth, round, pink-black lesions measuring 1–2 cm in diameter found mainly in children. They have increased cellularity and occur in nests within the upper dermis. Atypical nevi have a small risk of malignant degeneration.
Pigmented actinic keratosis
No
Premalignant lesions caused by sun exposure, sand paper texture, small, rough, erythematous, or brownish papules, often on the face, back, or neck, also called “cutaneous horn”.
Keratoacanthoma
No
Well-differentiated tumor originating from the pilosebaceous glands, develops rapidly and regresses spontaneously (outgrows blood supply and necroses) and presents as a cup-shaped tumor filled with keratin debris
Seborrheic keratosis
No
Common tumor in elderly presents as raised, discolored plaques, coin-like, waxy, “stuck-on” appearance.
Dysplastic nevus
No
Large, pigmented lesions, irregular border, frequently occur on the back, chest, buttocks, breast, and scalp and can be found in sun-exposed and sun-protected areas.
Melanoma
Yes
Proliferation of melanocytes, most common cause of death from skin cancer, presents as mole-like growth with “ABCD” (see below).
Squamous cell carcinoma
Yes
Proliferation of squamous cells characterized by formation of keratin pearls presents as ulcerated, nodular, mass with no telangiectasias, usually on the face (classically involving the lower lip).
Basal cell carcinoma
Yes
Most common cutaneous malignancy presents as elevated, pearl-like nodule with a central, ulcerated crater surrounded by telangiectasias (classically involving the upper lip).
Metastatic tumors to skin
Yes
In males, the most common sources are malignant melanoma (32 %), lung, colon, carcinoma of the oral cavity, larynx, and kidney. In females, the most common sources are breast (70 %), followed by melanoma, and ovary.
What Is the Most Likely Diagnosis?
In a patient presenting with a recently changed skin lesion that has become variegated and larger in diameter with an asymmetric, irregular border, the most likely diagnosis is melanoma. Additionally, the patient’s fair-colored skin, occupation as a lifeguard, and history of blistering childhood sunburns further increase his risk of developing skin cancer.
History and Physical
What Risk Factors for Skin Cancer Are Common to SCC, BCC, and Melanoma?
A common pathway for increased risk for skin cancer (SCC, BCC and melanoma) is excessive exposure to ultraviolet (UV) light, particularly UVB. Immunosuppression is another recognized risk factor. For SCC and BCC, the risk is greatest with cumulative long-term UV exposure. With melanoma, both blistering sunburns and overall sun exposure are risk factors. Skin cancer is also more common in patients who have fair-colored skin and hair and blue eyes.
What Factors During Childhood/Teen Years Are Associated with an Increased Risk of Skin Cancer?
A blistering sunburn in childhood or adolescence more than doubles the chance of developing skin cancer, as does the use of a tanning salon.
What Genetic Conditions Are Associated with an Increased Risk of Skin Cancer?
Xeroderma pigmentosum is a rare autosomal recessive condition that leads to photosensitivity due to deficient repair of DNA damaged by UV radiation. It leads to a very high rate of melanoma, BCC, and SCC at an early age.
What Occupations Are Highly Associated with Skin Cancer?
Occupations that involve long-term sun exposure place patients at higher risk, such as a lifeguard, farmer, construction worker, gardener, and field worker.
What Are Findings on Physical Examination that Differentiate a Benign Nevus from Melanoma?
The “ABCDEs” of melanoma (Table 36.1) can serve as a memory tool to help remember the common differentiating characteristics.
Table 36.1
“ABCDEs” of Melanoma
A | Asymmetry of lesion | Is the lesion round and symmetric or does it look asymmetric? |
B | Border irregularity | Do the borders of the lesion seem smooth and circumscribed or are they jagged and indistinct? |
C | Color variegation (different colors) | Does the lesion have one even pigmented color or does it have several shades of pigment in one lesion? |
D | Diameter > 6 mm | Is the lesion bigger than about the size of a pencil eraser? |
E | Evolution (changing lesion) | Are there any big changes such as rapid growth, bleeding, or ulceration in the lesion? |
Watch Out
Hair growth on a skin lesion suggests that it is a benign nevus. Melanomas destroy hair follicles.
What Is the Ugly Duckling Sign?
The ugly duckling sign is a concept that emerged after recognizing the limitations in the ABCDE mnemonic. Any skin lesion that looks different or out of place and thus an “ugly duckling,” in a nest of other similar appearing lesions is suspicious and recommended for biopsy.
What Is It Important to Inquire About and Examine Areas of Chronic Skin Inflammation?
Chronic skin inflammation is a known risk factor for SCC. It can develop in chronic open burn wounds (Marjolin’s ulcer), chronic venous ulcers, and longstanding skin infections such as hidradenitis suppurativa and human papillomavirus.
Watch Out
Chronically non-healing wounds should be biopsied to rule out malignancy.
On What Areas of the Skin Are Melanomas Most Likely to Occur in Non-white Ethnicities?
In African American, Asian, and Hawaiian populations, melanomas most often occur on areas of nonexposed skin with less pigment such as the palms, soles, mucous membranes, and nail regions.
What Is the Most Common Site of Melanoma in Men Versus Women?
For men, the back is the most common site, while the legs are the most common site for women.
What Is the Most Common Site of Digital Melanoma?
Great toe. Amputation and sentinel lymph node is the preferred treatment.
Does the Regular Use of SPF Protection Reduce the Risk of Skin Cancer?
Yes, regular daily use of an SPF 15 or higher sunscreen reduces the risk of developing squamous cell carcinoma and melanoma by about half.
Etiology/Pathophysiology
What Is a Nevi? Are Nevi a Risk for Malignant Transformation?
An additional risk factor for melanoma includes dysplastic nevus syndrome (autosomal dominant disorder) characterized by multiple dysplastic nevi with increased risk for progression towards melanoma (10 % risk).
From Where Does Melanoma Arise?
Melanoma originates from melanocytes, which are derived from neural crest cells. It can arise from a preexisting nevus or de novo as a new pigmented lesion (although a small percentage can be amelanotic).
What Is the Most Common Skin Cancer? Second Most Common? Which Skin Cancer Is Associated with the Greatest Number of Deaths?
Basal cell carcinoma is the most common skin cancer (and most common overall cancer), followed by squamous cell cancer, whereas melanoma accounts for the most deaths.
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