Nevus is a benign collection of pigment-producing cells (melanocytes) in the epidermis, dermis, or both.
Can be present at birth or shortly thereafter, or acquired throughout childhood, peaking during the third decade.
Seen in all races. Dysplastic or Clark's nevi are more commonly seen in white people.
Melanoma is the most important differential diagnosis when examining melanocytic nevi. Asymmetry, border irregularity, colour variegation, diameter >6 mm, and evolution or change in a pigmented lesion (ABCDEs) may signify concern for malignancy.
Diagnosis is usually clinical, although dermatoscopy and/or biopsy can be utilised to further examine the lesion in cases where there may be uncertainty as to the diagnosis or a concern for malignancy.
Important reasons for removal of a melanocytic nevus are: high clinical suspicion of melanoma; history of change in the lesion, supported by physical examination; and/or high suspicion of atypical features suggestive of melanoma.
Melanocytic nevi are a group of benign neoplasms or hamartomas made up of melanocytes, the pigment-producing cells of the epidermis. They can present in a variety of ways, most commonly as small, brown, flat macules, raised mammillated dome-shaped papules, bluish-grey macules and papules, and even amelanotic skin-coloured papules. Unless congenital, they first appear in childhood and are more common in people with light skin and eyes.
History and exam
Key diagnostic factors
- presence of risk factors
- presence since birth
- asymmetrical, indistinct or irregularly bordered, variably coloured papules with diameter >5 mm
- history of change in shape and colour
- asymptomatic (usually)
- multiple lesions
- flat, brown macule
- dome-shaped papule
- light brown background with speckled darker brown spots within
- blue-grey dome-shaped papule
- central pink-to-brown papule with a surrounding depigmented white ring
- pinkish-brown papule
- genetic predisposition
- ultraviolet exposure
- fair skin
- age: older children and young adults
1st investigations to order
Investigations to consider
- non-invasive imaging technologies
- total body photography
- whole genome sequencing
- pigmented lesion assay (PLA)
clinically suspicious for melanoma
- Seborrhoeic keratosis
- Solar lentigo
- Suspected cancer: recognition and referral
- The 2018 World Health Organization classification of cutaneous, mucosal, and uveal melanoma: detailed analysis of 9 distinct subtypes defined by their evolutionary pathway
Skin cancer (melanoma): what is it?
Skin cancer (melanoma): how is it diagnosed and treated?More Patient leaflets
- Log in or subscribe to access all of BMJ Best Practice
Use of this content is subject to our disclaimer