9th July 2023

Benign Lesions

Actinic keratosis (AK)

Premalignant lesions arising from chronic UV radiation. Often seen in older patients, fair skin, and sun-exposed sites. Present as multiple small flesh-coloured/yellow scaly macules/plaques with irregular borders. Often a clinical diagnosis. Risk of developing into SCCs and, therefore, should be treated. Topical creams (Imiquimod, 5-FU, Diclofenac) are often used. Surgical options include cryotherapy and curettage.

Leukoplakia

Leukoplakia refers to white-grey patches or plaques on the oral mucosa which are not characterised as any specific disease. Once a cause is established, this can be due to a variety of conditions, including candidiasis, lichen planus, and SCC. It is strongly associated with smoking and alcohol intake. Biopsy is often required to exclude SCC in-situ which can progress to invasive SCC if not treated. Therefore, depending on the cause, leukoplakia can be considered premalignant.

Dermatofibroma

Dermal fibroblast proliferation gives rise to a fibrous red/brown papule or nodule, known as cutaneous fibrous histiocytoma. May arise at sites of previous injury and often seen on the lower leg. Characteristically, the lesion dimples when squeezed, the dimple sign. Often a clinical diagnosis which requires no treatment. Recurrence is common if excised.

Keratoacanthoma 

Squamoproliferative lesions arising from the pilosebaceous unit on sun-exposed areas. Initially a papule, it rapidly becomes a nodule, often with a keratin core. Unclear aetiology, yet risk factors include UV, smoking, older age, and immunosuppression. Lesions regress over time. However, they are clinically challenging to distinguish from SCCs and, therefore, must be surgically excised for histological confirmation.

Seborrhoeic keratosis (SK)

Plaque with a classic ‘stuck-on’ like appearance of variable shapes, sizes, and colours. Texture varies from verrucous to smooth, and they can vary in number. Often sited on the torso and typically found in patients >50 years with fairer skin. Lesions are painless but sometimes pruritic. Often a clinical diagnosis that requires no treatment unless clothing friction causes irritation.

Capillary haemangioma

A benign proliferation of capillaries that present as red papules and whose frequency increases with advancing age. Histologically similar to a larger lobular form called pyogenic granuloma; a single red nodule which grows rapidly and can bleed and ulcerate. The cause is unknown but associated with trauma and hormones (oral contraceptives and pregnancy).