Benign Skin Tumors

A seborrheic keratosis is a common, benign, persistent epidermal lesion with variable clinical appearance.

It is one of the most common benign growths seen on the skin.

These keratoses have multiple clinical variations and can be easily be confused with other cutaneous malignancies.

Seborrheic keratoses are unusual before 30 years of age.

Most people develop at least one seborrheic keratosis in their lifetime.

Males and females are equally affected.

Lesions may be localized to the areola in both males and females.

The tendency toward multiple seborrheic keratoses may be inherited.

Keratoses are usually asymptomatic, but sometimes they are cosmetically bothersome.

Depending on the location, the lesion can be subject to irritation, trauma, and bleeding.

There are usually multiple lesions, which can arise at any site except the lips, palms, and soles.

The size and surface appearance of the lesions vary considerably.

Most seborrheic keratoses are between 0.2 and 2 cm in diameter, although larger lesions can occur.

Lesions may be flat or raised, and the surface may be smooth, velvety, or verrucous.

Retained keratin cysts may be seen just under the surface.

The color of lesions is extremely variable, including white, pink, brown, and black, and the color may vary within a single lesion.

Lesions tend to be sharply demarcated and round to oval in shape but can be asymmetric.

Thin seborrheic keratoses have a characteristic “stuck-on” appearance and waxy texture.

Thicker keratoses have an elevated surface that tends to crumble when rubbed or picked.

Dermatosis papulosa nigra describes the darkly pigmented seborrheic keratoses of the face seen more commonly in African Americans.

Dermatosis papulosa nigra lesions are 1- to 2-mm, dark-brown keratotic papules concentrated around the eyes and upper cheeks, with an incidence of 30% to 35% in African American people.

Stucco keratoses describe the small, white, firm seborrheic keratoses more commonly found on the lower legs and ankles of older white people.

Inflamed seborrheic keratosis is a clinical description for a seborrheic keratosis with clinically obvious inflammation; there may be edema, erythema, and hemorrhage.

The sign of Leser–Trélat is the sudden explosive onset of numerous seborrheic keratoses in association with internal malignancy.

Several histologic subtypes of seborrheic keratosis are recognized.

Acanthosis, hyperkeratosis, and papillomatosis are universal features.

The degree to which these features develop varies considerably within individual lesions and among subtypes.

Horn cysts and pseudohorn cysts are usually present.

The degree of melanin pigment varies from almost none (stucco keratosis) to extreme (melanoacanthoma).

Inflamed seborrheic keratoses show marked dermal inflammation, sometimes making the diagnosis difficult.

Unless disturbed, seborrheic keratoses tend to persist and grow slowly and become elevated with time.

Some lesions may be removed by trauma, especially if located in the flexural skinfold areas.

Raised or pedunculated seborrheic keratoses may be indistinguishable from skin tags and compound melanocytic nevi.

Flat seborrheic keratoses may mimic spreading pigmented actinic keratosis or superficial spreading melanoma. If doubt exists, a skin biopsy should be performed.

Although seborrheic keratoses have no malignant potential, there are rare reports of melanoma, basal cell carcinoma, and squamous cell carcinoma developing within a seborrheic keratosis.

A biopsy should be performed for a significantly changing seborrheic keratosis, looking for a malignancy.

Treatment may be indicated for symptomatic lesions.

Lesions in areas of friction and frequent trauma often become irritated and symptomatic.

Removal is often requested for discomfort or for cosmetic reasons.

Patients should be informed that cosmetic removal of seborrheic keratoses is not usually covered by medical insurance.

Cryosurgery is effective for flat or minimally raised lesions.

Thicker lesions are best removed by cautery and curettage under local anesthesia.

Residual scarring, if any, is minimal. Applying gentle pressure to the surrounding skin often provides enough tension to allow for easy curettage of lesions.

Hypopigmentation and hyperpigmentation are possible side effects of cryotherapy or any method of removal.

Seborrheic keratoses are common benign growths with multiple variants that can mimic other, more worrisome skin tumors.

Removal is not necessary unless lesions become inflamed and symptomatic.

Some keratoses are heavily pigmented, resembling melanoma, and therefore may need histologic confirmation.

When dermatologists unknowingly remove melanomas, it is thought that they are seborrheic keratoses clinically in 85% of cases.

Skin tags are common benign fleshy papules occurring in the skinfolds.

Skin tags, or acrochordons, are uncommon before 30 years of age but are common thereafter.

Women are affected more often than men.

Roughly 25% of adults have at least one skin tag.

Most patients with skin tags have only a few lesions.

They are more common in overweight persons.

There may be a familial tendency toward multiple skin tags.

Undisturbed lesions are usually asymptomatic.

As a result of their location, skin tags may become irritated by friction, jewelry, or clothing.

They may become tender when traumatized, twisted, torn, or thrombosed.

A skin tag is a skin-colored or brown 1- to 5-mm papule.

Papules may be flat or filiform, although most are soft, fleshy, and pedunculated on a thin stalk.

The axillae are the most common location, followed by the neck.

Lesions also occur on the eyelids as well as in other intertriginous areas, such as the inframammary and inguinal creases.

A previously reported association between skin tags and colonic polyps has not been confirmed by further studies.

Skin tags are part of Birt–Hogg–Dubé syndrome, which also includes trichodiscomas and fibrofolliculomas of the face, neck, and chest. Patients with this syndrome may have associated renal cell carcinoma, colonic adenomas, pulmonary cysts, and medullary carcinoma of the thyroid gland.

Skin biopsy confirms a papule with a characteristic thinned epidermis and a loosely arranged fibrous stroma with capillaries.

Left undisturbed, skin tags persist indefinitely or fall off unknowingly.

With torsion, skin tags may become thrombosed and tender.

With this acute change, patients usually seek care because they are concerned about skin malignancy.

Thrombosed skin tags often appear black, hemorrhagic, or both.

Any delay in seeking care allows the residual skin tag time to fall off on its own; thus no residual lesion is seen.

Warts

Nevi

Seborrheic keratosis

Asymptomatic skin tags do not require treatment.

Patients often request removal because of tenderness or for cosmetic reasons.

Patients should be informed that medically unnecessary removal of skin tags is usually not covered by medical insurance.

Skin tags are best treated by scissors excision with or without local anesthesia.

Electrocautery and cryosurgery can also be used.

The need to submit all skin tags for histologic review has been a topic of debate in recent years.

Many dermatologists feel that histologic confirmation is usually not necessary.

Skin tags do not normally present a diagnostic dilemma.

They can be inflamed, thrombosed, or tender and require treatment.

Skin tags around the eyelids may resemble other skin tumors and may need a biopsy for confirmation.

Dermatofibroma is a common, benign, indolent, dermal papule most commonly occurring on the legs of adults.

It can be pigmented and confused with melanoma.

Dermatofibromas arise spontaneously in adults and occasionally in children.

The etiology is unknown.

The lesions occur more often in women.

Lesions on the legs of women are subject to repeated trauma from shaving and can be annoying.

Most are asymptomatic, but pruritus and tenderness may occur.

Controversy exists as to whether the lesion represents a spontaneous benign neoplastic process or reactive hyperplasia in response to injury, but most patients do not recall a specific trauma to the area.

Some patients note itching when the lesion is first noted and attribute this to an insect bite.

Dermatofibromas tend to persist indefinitely while remaining stable in size and appearance.

Discrete, firm, pink dermal papules 3 to 5 mm in diameter are typical, but occasionally they can be larger than 3 cm.

Most dermatofibromas are dome shaped, although some are depressed below the surrounding skin surface.

The lesion is fixed within the skin but is movable over the underlying subcutaneous fat.

On palpation, the lesion feels like a firm button and puckers and retracts below the surface with palpation.

Dermatofibromas are typically flesh-colored to pink with a poorly defined rim of tan to brown pigmentation.

Rarely, lesions may be blue to black as a result of hemosiderin deposition and resemble melanoma.

The surface may be smooth and shiny to scaly or excoriated.

Although dermatofibromas may arise on any cutaneous surface, most are found randomly distributed on the extremities.

Lesions can be solitary or multiple.

Skin biopsy shows a focal unencapsulated proliferation of spindle-shaped cells resembling fibroblasts, histiocytes, and collagen.

Dermatofibromas attain their maximum size over months to years and then persist indefinitely.

Depending on location, lesions may be subject to repeated trauma from shaving or friction from clothing and footwear.

Lesions with large amounts of hemosiderin deep within the tumor may be blue to black and suggestive of nodular melanoma or pigmented dermatofibrosarcoma protuberans. Biopsy is warranted in such cases.

Dermatofibroma can clinically mimic melanoma with a central pink nodule and surrounding pigmentation.

Dermatofibrosarcoma protuberans resembles dermatofibroma histologically and, less commonly, clinically.

This insidious malignancy usually occurs on the trunk and presents as a slow-growing, often recurrent, poorly defined red-purple nodule or plaque.

Overall, the histologic findings are similar to those of dermatofibroma, so a superficial biopsy may be falsely reassuring.

Deep punch or excisional biopsy that includes subcutaneous fat confirms that dermatofibrosarcoma protuberans is more cellular than most dermatofibromas.

Malignant cells extend into the subcutaneous fat.

Dermatofibromas are benign skin tumors that do not require treatment unless they are symptomatic, repeatedly traumatized, or cosmetically bothersome. The patient should be assured that the lesion is benign.

Surgical excision with primary closure is the treatment of choice for symptomatic lesions.

Caution should be used when removing lesions for cosmetic reasons because the final appearance of the surgical scar may be less cosmetically acceptable than the original lesion.

If the lesion is incompletely excised by shave excision, the patient should be warned of possible recurrence.

Intralesional corticosteroid injection has been used to flatten elevated lesions. This form of treatment produces unpredictable results and is generally not recommended.

Dermatofibromas should be stable in size, appearance, and color. If they are not, they should be biopsied.

Pigmented lesions that are suspected to be traumatized should be biopsied.

A shave biopsy is not appropriate when the diagnosis is in question.

An excision is optimal so that the entire lesion, including the deep dermal component, can be evaluated histologically.

A keloid is an exuberant scar that extends beyond the area of trauma, injury, or surgical scar.

A hypertrophic scar is an exaggerated healing response to trauma, injury, or surgical scar.

Males and females are affected with equal frequency.

Keloids can occur at any age but tend to occur before age 30 years.

Keloids are more common in darker skinned patients than white people.

Hypertrophic scars and keloids can arise at any skin site.

Most occur on the chest or head and neck area, including the earlobe.

Lesions occur at sites of trauma and injury, which includes surgery, burns, piercing, acne, and sites of inflammation.

Normal scars are usually red and firm during the initial weeks to months of healing.

Itching and tenderness are common for normal scars, hypertrophic scars, and keloids.