Summary
Benign skin tumors are noncancerous skin growths and include hemangiomas, angiomas, angiokeratomas, seborrheic keratoses, dermatofibromas, lipomas, dermal cylindromas, acrochordons, epidermoid cysts, and sebaceous hyperplasia. Benign skin tumors are typically diagnosed based on the appearance of the lesion, but a biopsy may be performed to rule out malignancy if the diagnosis is uncertain or the lesion has concerning features, such as a rapid increase in size. Removal (e.g., with surgical excision, cryosurgery, or electrosurgery) is typically only indicated for suspected malignancy, cosmetic reasons, or if symptoms are bothersome.
For other benign skin disorders, see “Hypertrophic and keloid scars” and “Collection of dermatological disorders.”
Vascular skin tumors
Infantile hemangioma (strawberry hemangioma)
See “Strawberry hemangioma.”
Cherry angioma [1][2][3]
Epidemiology
- Most common benign vascular tumor
- Most commonly occurs in adults > 30 years of age [2]
- Incidence increases with age
Pathophysiology
Cherry angiomas are a benign proliferation of dilated mature capillaries and postcapillary venules.
Etiology
- Unknown; chemical exposure or hormonal factors may be involved
- Associated with Fabry disease [1]
Clinical features
- Multiple dome-shaped papules or macules
- Typically on the trunk and upper extremities, but can occur anywhere on the body
- 1–5 mm in diameter [2]
- Well-demarcated
- Bright red or dark purple; if thrombosed, may appear black
- Compressible and blanch with pressure
- Typically asymptomatic
- May bleed profusely with trauma
Diagnostics
- Diagnosis is typically clinical.
- Excisional biopsy: if malignancy is suspected [4]
- Genetic testing: if Fabry disease is suspected [1]
Differential diagnoses
- Pyogenic granuloma
- Petechiae
- Melanoma [4]
- Blue nevus [4]
Treatment
- Indicated for bleeding lesions or cosmetic reasons
- Options include:
- Electrodessication
- Laser ablation
- Surgical excision (e.g., shave excision)
Prognosis [4]
- No malignant potential
- No spontaneous regression
Pyogenic granuloma [1][2][5]
Definition
A pyogenic granuloma is a benign vascular tumor characterized by rapid growth and a tendency to bleed easily.
Epidemiology
- Most commonly develops in childhood
- Occurs in ∼ 5% of pregnancies (especially in the second and third trimesters) [6]
Etiology
Etiology is unclear; pyogenic granulomas may be associated with:
Clinical features [7]
- Solitary polypoid or pedunculated nodule
- Can occur anywhere, but often found on the mucus membranes, head, neck, trunk, hands, and/or feet
- Rapid growth followed by stabilization of size (typically < 2 cm) [5]
- Well-demarcated
- Wide range of colors (e.g., yellow, bright red, purple)
- Friable, scaly collarette, may ulcerate
- Tendency to bleed easily, e.g. after minor trauma
Diagnostics
- Diagnosis is typically clinical.
- Excisional biopsy: if malignancy is suspected
Differential diagnoses
- Amelanotic nodular melanoma
- Squamous cell carcinoma, basal cell carcinoma
- Angiosarcoma, Kaposi sarcoma [7]
- Spitz nevi
Treatment
- Lesions are typically removed because they proliferate rapidly and bleed easily.
- Options include:
- Laser ablation
- Surgical excision (e.g., shave excision) with electrodesiccation
- Refer patients with facial or recurrent lesions to dermatology.
Prognosis [7]
- Regression occurs in some cases.
- Lesions may recur or form satellite lesions after removal.
Angiomatosis
See “Bacillary angiomatosis” for further information.
Angiokeratoma [2][8][9]
Definition
An angiokeratoma is a benign vascular ectasia of the superficial dermal blood vessels with overlying hyperkeratosis of the epidermis.
Pathophysiology
Angiokeratomas may develop due to increased venous pressure (e.g., pregnancy, hemorrhoids).
Etiology
- Unknown
- May be related to genetic factors or local trauma
Clinical features
- General features may include: [10]
- Additional features depend on the subtype.
| Angiokeratoma subtypes [2][8][9] | |||
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| Angiokeratoma of Fordyce | Solitary angiokeratoma [11] | Angiokeratoma corporis diffusum | |
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Diagnostics
- Diagnosis is typically clinical.
- Dermatoscopy: dark lacunae with a white veil [12]
- Excisional biopsy: if malignancy is suspected
Differential diagnosis [12]
- Other vascular lesions: cherry angioma, pyogenic granuloma
- Pigmented lesions: melanocytic nevi, Spitz nevi, melanoma
Treatment
- Indicated for suspected malignancy, cosmetic reasons, or if symptoms are bothersome
- Options include:
- Surgical excision
- Electrosurgery
- Laser ablation
- Cryosurgery
Prognosis
Angiokeratomas have no malignant potential.
Seborrheic keratosis
Definition [13]
Seborrheic keratosis is a benign growth of immature keratinocytes.
Epidemiology [1]
Seborrheic keratosis is the most common benign skin tumor in adults > 30 years of age.
Etiology [1]
- Hereditary
- Underlying malignancy (e.g., gastric adenocarcinoma) can cause paraneoplastic seborrheic keratoses (Leser-Trélat sign).
Clinical features [1][2][3]
- Single or multiple soft papules or plaques that appear stuck on
- Located on the trunk, upper extremities, face, and/or scalp
- Texture is greasy, waxy, velvety, or warty
- 1 mm to 6 cm in diameter [14]
- Sharply demarcated
- Yellow-brown
- May become irritated (by external trauma or spontaneously) and bleed
- Pruritic (rarely)
Diagnostics [1][2]
- Diagnosis is typically clinical; horn cysts on dermatoscopy are pathognomonic.
- Excisional biopsy: if melanoma is suspected
- Evaluation for underlying malignancy (see “Diagnostics of cancer of unknown primary”): indicated for patients with Leser-Trélat sign [3]
Histopathology [13]
There are multiple histopathological variants of seborrheic keratosis. Features may include:
- Numerous monomorphic keratinocytes with papillomatosis
- Numerous melanocytes
- Immature keratinocytes with small keratin-filled cysts (horn cysts)
Differential diagnoses [1][2]
- Macular lesions
-
Papular or plaque lesions
- Atypical nevus
- Melanoma
- Pigmented basal cell carcinoma
Treatment [1]
- Indicated for suspected malignancy, cosmetic reasons, or if symptoms are bothersome
-
Options include:
- Cryosurgery
- Curettage
- Electrodesiccation
- Laser ablation
- Surgical excision (e.g., shave excision)
Prognosis [2]
- No malignant potential
- Increase in number and size with age
Dermatofibroma
Definition [2]
A dermatofibromas is a common, small, benign dermal nodule.
Epidemiology [1]
Etiology [1]
- Not fully understood
- Sometimes related to an insect bite or trauma
Clinical features [1][2]
- Solitary or multiple firm papules or nodules [1]
- Most commonly on the lower extremities but can occur anywhere on the body
- Lateral compression (pinching) causes a central dimple in the lesion (dimple sign)
- Slow-growing (to ∼ 3–10 mm in diameter), then remain the same size for years
- Poorly dermarcated with faded margins
- Variable color (skin-colored, tan, pink, brown)
- Frequently asymptomatic
- May be pruritic or tender and may bleed with trauma
Diagnostics [1]
- Diagnosis is typically clinical.
- Excisional biopsy: if malignancy is suspected
Histopathology [1][14]
Typical features include fibroblast and histiocyte proliferation.
Differential diagnoses [1][2][14]
- Dermatofibrosarcoma protuberans
- Nodular melanoma
- Kaposi sarcoma
- Carcinoma, including basal cell carcinoma
- Benign conditions: cellular dermatofibroma, papulonodular mucinosis, blue nevus, scar, pilar cyst
Treatment [1]
- Indicated for suspected malignancy, cosmetic reasons, or if symptoms are bothersome
- Options include:
- Cryosurgery
- Laser ablation
- Punch excision
- Surgical excision
Prognosis
Lipoma
Definition [1]
A lipoma is a common, benign, soft tissue mesenchymal tumor, usually subcutaneous.
Etiology [2][3]
- Spontaneous
- May develop following trauma
- Rare disorders, e.g.:
- Familial multiple lipomatosis (an autosomal-dominant disorder characterized by multiple lipomas)
- Dercum disease
Epidemiology [1]
- Most common soft tissue tumor
- Prevalence: 1%
Clinical features [1][16]
- Single or multiple round, soft, rubbery mobile, discrete nodules or masses
- Typically on the trunk, neck, and/or extremities
- Slow-growing; typically < 6 cm in diameter, but may be larger
- Skin-colored
- Typically nontender and asymptomatic, but large lesions may cause compressive and/or obstructive symptoms [1]
Diagnostics [1][17][18]
- Diagnosis is typically clinical.
- Ultrasound can help confirm the diagnosis. [19]
- Obtain an MRI (preferred) or CT with and without IV contrast for further evaluation if:
- Mass is > 5 cm
- Mass is; deep to the fascia (on examination, may be firm or fixed instead of freely mobile)
- Other features are concerning for malignancy (e.g., mass is rapidly growing or located on the thigh, older age)
- If MRI or CT findings are not consistent with a lipoma, refer to a multidisciplinary sarcoma center for further management.
Refer directly to a multidisciplinary sarcoma team if clinical features strongly suggest soft tissue sarcoma (i.e., mass > 5 cm and/or increasing size, associated pain, and/or deep site). [20]
Histopathology [1][17]
- Normal mature adipocytes of mesenchymal origin
- Fibrous capsule
Differential diagnoses [1]
Treatment
- Indicated for suspected malignancy, cosmetic reasons, or if symptoms are bothersome [1][3][17]
- Options include:
- Minimal incision extraction
- Surgical excision
- Liposuction [3]
Prognosis [17]
- No malignant potential
- If excised, recurrence occurs in < 5% of cases.
Dermal cylindroma
Definition [2]
A dermal cylindroma is a rare benign skin appendage tumor.
Etiology [2]
Etiology is unknown.
Subtypes [21]
-
CYLD cutaneous syndrome
- An autosomal-dominant familial cylindromatosis. [21]
- Multiple coalescing tumors (in some cases, hundreds) on the head (known as “turban tumor”) and/or neck
- Tumors include cylindromas, trichoepitheliomas, and spiradenomas and start to develop around puberty.
- Malignant transformation occurs in ≤ 10% of individuals. [21]
Clinical features [2][22]
- Smooth nodule or papule
- Typically a solitary tumor on the scalp, face, and/or trunk; multiple tumors in CYLD cutaneous syndrome [7]
- ≤ 6 cm in diameter [23]
- Well-demarcated
- Pink or reddish
- Slow-growing
Diagnostics [24]
- Biopsy is required.
- Genetic testing: indicated for suspected CYLD cutaneous syndrome
Treatment [23]
- Indicated for CYLD cutaneous syndrome, cosmetic reasons, or if symptoms are bothersome
- Options include:
- Surgical excision
- Scalp excision with skin grafting
- Other: curettage, cryosurgery, electrosurgery, dermabrasion
Prognosis [24]
Malignant transformation is very rare.
Acrochordon (skin tag)
Definition [1]
An acrochordon is a small, sometimes slightly discolored papillomatous skin lesion that most commonly arises in skin folds.
Epidemiology [1]
- Commonly occurs in adults > 50 years of age
- Prevalence: 25–45%
Etiology [1]
- Thought to be caused by frequent irritation, e.g., skin rubbing on skin
-
Associated with:
- Hormonal changes (e.g., pregnancy, acromegaly)
- Metabolic syndrome (e.g., obesity, type 2 diabetes mellitus)
- Perianal acrochordons are associated with Crohn disease. [25][26]
Clinical features [1][2]
- Smooth, round or oval pedunculated papule on a narrow stalk
- Found in locations prone to friction (e.g., lower neck, axilla, inframammary fold, inguinal regions)
- 2–5 mm in height, may be larger [1]
- Well-demarcated
- Skin-colored or darker
- Typically asymptomatic
Diagnostics [1]
- Diagnosis is typically clinical.
- Excisional biopsy: if malignancy is suspected
Differential diagnoses [1]
- Seborrheic keratosis
- Neurofibromas
- Senescent intradermal nevus, pedunculated nevus
- Basal cell carcinoma, squamous cell carcinoma
Treatment [1][3]
- Indicated for cosmetic reasons or if symptoms are bothersome
- Options include:
- Surgical excision (e.g., shave excision or with scissors)
- Cryosurgery
- Electrodesiccation
Refer patients with eyelid lesions to dermatology or plastic surgery for removal. [1]
Cysts
Epidermoid cyst [1][2][8]
Epidermoid cysts are also called epidermal inclusion cysts, epidermal cysts, and keratin cysts. [1]
Definition
An epidermoid cyst is an encapsulated lesion containing keratin and lipids and lined with stratified squamous epithelium.
Epidemiology
- Typically occurs in adulthood
- Most common cutaneous cyst
Etiology
The etiology involves the implantation of epithelium within the dermis.
Clinical features
- Dome-shaped, firm, mobile, dermal to subcutaneous nodule or mass
- Typically a solitary lesion found on the face, head, neck, trunk, and/or genitals
- Grows slowly over years or remains stable (∼ 0.5–5 cm) [2]
- Well-demarcated
- Skin-colored with a central black punctum, erythematous when inflamed
- Does not dimple when pinched
- Typically painless; painful if ruptured, which may subsequently lead to infection
- Cyst contents: thick cream-colored keratinaceous material with an unpleasant odor
Diagnostics
- Diagnosis is typically clinical.
- Incision and drainage: if infection is suspected [3]
- Excisional biopsy: if malignancy is suspected
Differential diagnosis
- Lipoma
- Infection: boil, abscess [1]
- Other cysts: e.g., trichilemmal cyst, sebaceous cyst
Treatment
- Asymptomatic cysts do not require treatment.
- For cysts on the face: Refer to dermatology or plastic surgery.
- Ruptured or inflamed cysts:
- May resolve spontaneously (but frequently recur)
- Intralesional steroids (e.g., triamcinolone) may accelerate resolution
- Infected cysts: antibiotics, incision and drainage
-
Surgical excision is performed:
- If desired for cosmetic reasons or bothersome symptoms
- After resolution of a ruptured, inflamed, or infected cyst to prevent recurrence
- If lesions occur in multiple and/or in atypical locations (e.g., fingers, toes, legs), evaluate for Gardner syndrome.
Cysts occurring on the face should be referred to a dermatologist or plastic surgeon. [1]
Trichilemmal cyst (pilar cyst) [2][8]
Definition:
A trichilemmal cyst is a cyst that forms around a hair follicle.
Epidemiology
- Second most common skin cyst
- Commonly occur in middle-aged females
Etiology
Etiology may be genetic.
Clinical features
- Dome-shaped, firm, mobile, subcutaneous nodule or mass [2][8]
- Often multiple lesions, most commonly located on the scalp
- 0.5–5 cm [2]
- Well-demarcated
- Skin-colored with no central punctum
- Painful if infected or inflamed
- Cyst contents: dense keratinaceous material
Diagnostics
- Diagnosis is typically clinical.
- Culture: if infection is suspected
- Excisional biopsy: if malignancy is suspected
Differential diagnosis [27]
- Other cysts, e.g., epidermoid cyst, sebaceous cyst
- Basal cell carcinoma (especially nodular), squamous cell carcinoma
Treatment
Treatment consists of surgical excision.
Sebaceous hyperplasia
Definition [1]
Sebaceous hyperplasia is a benign and common disorder of the sebaceous glands in which sebocytes become enlarged.
Epidemiology [1][2]
- Middle-aged and older adults
- Present in one-fourth of adults > 30 years of age [8]
- Occur in immunosuppressed individuals on cyclosporine
Etiology [8]
Etiology is unknown.
Clinical features [1][2]
- Solitary or multiple soft, dome-shaped papule(s) with central umbilication
- Typically near hair follicles of the face, e.g., on the forehead, cheeks, and/or chin
- 1–4 mm
- Skin-colored or pale yellow, shiny
- Asymptomatic
- Lateral compression may produce sebum in the umbilication
Diagnostics [1]
- Diagnosis is typically clinical.
- Dermatoscopy: aggregation of white to yellow sebaceous globules (cumulus sign) surrounded on the periphery by superficial vessels [28][29]
- Excisional biopsy: if malignancy is suspected
Differential diagnosis [2]
Treatment [1][2]
- Indicated for cosmetic reasons or if symptoms are bothersome
- Options include:
- Topical bichloroacetic acid [8]
- Removal of the lesion (e.g., with electrosurgery, cryotherapy, phototherapy, laser ablation, or shave excision)
- Systemic isotretinoin for diffuse lesions
Removal of deeper parts of the lesion, e.g., with curettage, can cause pitted scarring. [8]