SEBORRHEIC KERATOSES

Seborrheic keratoses may be the most common benign tumor of the skin. Typically, they are scaly (hyperkeratotic), brown (hyperpigmented), often somewhat greasy plaques that vary in size and thickness and often appear to be stuck onto the skin surface (Fig. 1). They occur on any surface except the palms, soles, and mucosa. They are common in adults, more so with advanced age, and unusual in children. Their cause is unknown, but a genetic predisposition may be present in some families. The sudden eruption of many, often pruritic seborrheic keratoses on the trunk (Leser-Trélat sign) has been implicated as a cutaneous marker of internal malignancy, commonly gastric adenocarcinoma. Evaluation of such patients should include upper endoscopy and age-appropriate cancer screening.

Figure 1 Seborrheic keratosis.

Therapy is usually not necessary unless plaques are pruritic, irritated or inflamed, or of cosmetic concern. When necessary, cryotherapy (liquid nitrogen) or curettage is usually adequate. If the clinical diagnosis is uncertain, a biopsy is warranted.

DERMATOSIS PAPULOSA NIGRA

Dermatosis papulosa nigra is a condition of hyperpigmented, hyperkeratotic plaques similar to seborrheic keratoses and acrochordons (skin tags), both clinically and histologically. Dermatosis papulosa nigra growths are common and usually are found on the face and neck, with a particular predilection for periorbital skin of darkly pigmented persons (Fig. 2).

Figure 2 Dermatosis papulosa nigra.

Approximately 50% of the black population has these benign growths, and women are more affected than men by a ratio of 2 : 1.

Therapy is usually not necessary unless the growths become itchy or irritated, although many people desire treatment for cosmetic reasons. Treatment options include scissor excision, curettage, or cryotherapy, all of which can produce hypo- or hyperpigmentation.

SEBACEOUS HYPERPLASIA

Sebaceous hyperplasia is a benign enlargement of sebaceous glands surrounding a follicle characterized by small flesh-colored to yellow papules, often with a central dell, on the face of adults (Fig. 3).

Figure 3 Sebaceous hyperplasia.

More common in men and in patients with organ transplants, sebaceous hyperplasia lesions are often numerous, and individual papules can resemble basal cell carcinomas (particularly when accompanied by telangiectasias) or even molluscum contagiosum.

Treatment, primarily for cosmesis, includes cryotherapy, curettage, and laser therapy.

EPHILIDES (FRECKLES)

Ephilides are small, discrete, hyperpigmented macules on the sun-exposed skin of fair-complected individuals, usually redheads and blonds.

Ephilides are not growths per se; they represent focal increased melanin in the skin, and they tend to darken in the summer with increased sun exposure and lighten in the winter. When present in large numbers, they indicate excessive sun (photo) damage and an increased risk of sun-induced skin cancer, including melanoma, basal cell carcinoma, and squamous cell carcinoma.

Ephilides are benign and harmless, and treatment is not necessary. Topical bleaching creams, chemical peels, or cryotherapy can lighten ephilides of cosmetic concern.

LENTIGINES (LIVER SPOTS)

Lentigines are hyperpigmented macules or patches that can resemble nevi (moles). Usually pale tan to brown, they typically appear in white adults and increase in number with advancing age (Fig. 4).

Figure 4 Solar lentigo.

Lentigines tend to occur on the sun-exposed skin of the face, neck, upper trunk, forearms, and hands. Unlike ephilides, lentigines are the result of epidermal hyperplasia and of variable proliferation of melanocytes and subsequent melanization. Lentigines are benign, but they occasionally transform into lentigo maligna (superficial melanoma). If change occurs in a lentigo (e.g., rapid growth, change in color or surface contour), a dermatologic evaluation is warranted and a biopsy may be necessary. Many lentigines indicate excessive photodamage and increased risk of sun-induced skin cancer.

Like treatment for ephilides, treatment for lentigines is primarily for cosmetic reasons. Options include cryotherapy, chemical peels, laser therapy, and bleaching creams containing hydroquinone.