Common benign skin lesions

What is a benign skin lesion?

A benign skin lesion is a non-cancerous skin growth.

Who gets benign skin lesions?

Any individual from any age group can present with a benign skin lesion.

What are the features of benign skin lesions?

The features in common for benign skin lesions include:

• Symmetry in shape, colour and structure
• Stable or slowly evolving
• Absence of spontaneous bleeding (bleeding or ulceration may be due to recent injury).

Benign lesions can be classified by their cellular origin: melanocytic, keratinocytic, vascular, fibrous, fat, and so on,

Which are the common melanocytic lesions?

Common benign skin lesions of melanocytic origin include the ephilis, lentigo simplex, and melanocytic naevus.

Ephilides are genetically determined well-defined small brown macules with the following characteristics:

• 1–4 mm in diameter
• Tan or brown colour
• Located in areas exposed to the sun such as the face and forearms.
• Increased melanin deposition in the basal keratinocyte on biopsy [1,2].

Lentigo simplex is not sun-induced. It has the following characteristics:

• Well-circumscribed, uniform brown to black macule
• Located on mucous membrane or skin, including palms and soles
• Develops during childhood or young adult life [1,2].

A melanocytic naevus can be histologically classified as junctional, compound, or dermal naevi depending on the location of nests of naevus cells.

A junctional naevus has naevus cells at the base of the epidermis.

• A junctional naevus is well-circumscribed pigmented macule with regular but fading borders.
• The number and appearance of junctional naevi depend on sun exposure, fluctuating hormonal levels, and immunosuppression [1,3].

Ephilides

Lentigo simplex

Junctional naevus

A compound naevus has papular and flat components due to junctional and dermal naevus cells.

• The compound naevus is usually a pink or brown, dome-shaped papule surrounded by macular pigmentation [3].
• Most lesions arise during childhood.

A dermal naevus is characterised by naevus cells in the dermis.

• The dermal naevus is an elevated papule.
• It can be brown, blue, black or skin coloured.
• Dermal naevi arise in childhood but mature during early adult life.

Compound naevus

Dermal naevus

Papillomatous dermal naevus

Which are the common keratinocytic lesions?

Benign keratoses include solar lentigo and seborrhoeic keratosis.

A solar lentigo is a sun-induced pigmented macule.

• Solar lentigines vary from small to large size and are usually tan to brown-black.
• The lesions are mostly uniformly pigmented with a sharp border.
• They arise in adult life and are prevalent in older people [1,2].

Solar lentigo

Solar lentigo

Solar lentigo

Seborrhoeic keratosis presents as a variable warty plaque.

• Seborrhoeic keratosis has a dull, verrucous, or waxy surface with a classical stuck-on appearance.
• The shape and structure are often irregular and varies over time.
• They can be yellow to brown to black in colour or made up of several colours.
• Skin biopsy reveals a papillomatous epidermis with a thick basal layer and presence of keratin-filled cysts [1,4].

Seborrhoeic keratosis

Seborrhoeic keratosis

Seborrhoeic keratosis

Epidermoid cyst is a follicular nodule with a central punctum.

• This type of cyst can be skin-coloured to off-white and is a dome-shaped papule or nodule
• Cheesy or yellowish keratin can be expressed through the punctum or removed by incising the cyst.
• The epidermal cyst is lined with flat epidermal cells and has a granular layer surrounding laminated keratin [1,2].

Epidermoid cyst

Epidermoid cyst

Palpating an epidermoid cyst

Corns and calluses are localised areas of thickened skin induced by pressure

• A corn (small tender papule) or callus (thickened non-tender plaque) is most often located on a pressure area of the hand or foot.
• A soft corn is a scaly plaque while hard corn is a firm papule with a translucent central core [1,2].

Corn (clavus)

Corn (clavus)

Calluses

Sebaceous hyperplasia occurs on the forehead and cheeks of adults.

• It presents as one or more dome-shaped papules with central umbilication.
• Uniform yellow lobules are seen on dermoscopy [1,2].

Sebaceous hyperplasia

Sebaceous hyperplasia

Sebaceous hyperplasia

Which are the common lesions of vascular origin?

An angioma is due to the proliferation of the endothelial cells.

• A superficial angioma is a bright red colour and a deeper angioma is purple or blue.
• Angiomas are commonly nodular or macular lesions of varying sizes.

Cherry angioma

Cherry angioma

Cherry angioma

A pyogenic granuloma is a vascular response to trauma and bacterial infection.

• It presents as a rapidly growing friable nodule on fingers, toes, or facial sites.
• They have a yellow to violaceous colour.
• The pyogenic granuloma is surrounded by a scaly collarette.

Pyogenic granuloma

Pyogenic granuloma

Pyogenic granuloma

Which are the common fibrous lesions?

Dermatofibroma is a reactive lesion that presents as one or more firm dermal papules.

• The dermatofibroma is pink, tan or brown.
• It forms a dimple when pinched.
• A skin biopsy shows fibrohistiocytic cell proliferation with entrapment of collagen at the periphery [1,2].

Which are the common subcutaneous lesions?

The lipoma is the most common benign soft-tissue tumour.

• A lipoma presents as a soft, rubbery, freely mobile mass that is usually found on the back, neck, or trunk.
• Skin biopsy shows white adipose tissue in the subcutaneous layer [1,2].

Lipoma

Lipoma

Painful lipomas

What is a skin tag?

The most common type of skin tag is also called acrochordon.

• An acrochordon is a soft, fleshy papule that is almost always pedunculated.
• They vary in diameter from 1 to 6 mm.
• On biopsy, there is a fibrovascular core covered by normal squamous epithelium [2].

Skin tags

Skin tag

Skin tag