Dysplastic nevus syndrome
Dysplastic nevus syndrome is a skin condition marked by the presence of numerous atypical moles, known as dysplastic nevi. This syndrome is particularly prevalent among individuals with light skin, hair, and a history of sunburn, and it significantly elevates the risk of developing melanoma, a type of skin cancer. Individuals with a family history of dysplastic nevi and melanoma, especially those with multiple dysplastic nevi, face a very high likelihood of developing melanoma, which is referred to as familial atypical mole and melanoma (FAMM) syndrome.
Symptoms of dysplastic nevi include asymmetrical moles with irregular borders and varying colors, typically larger than 5 millimeters. While the exact cause of dysplastic nevi is still debated, factors like excessive sun exposure and weakened immunity may contribute to their development. In the United States, dysplastic nevi are found in 2 to 5 percent of the white population, with higher prevalence rates in countries like Australia and Sweden.
Screening for dysplastic nevus syndrome involves thorough skin examinations and family history assessments, with biopsies used to distinguish between dysplastic nevi and melanoma. Although there is no definitive treatment, preventive measures such as sun protection and regular skin monitoring are crucial for managing the condition and reducing the risk of melanoma.
Subject Terms
Dysplastic nevus syndrome
Also known as: Atypical mole syndrome, dysplastic mole, Clark’s nevus
Related conditions: Malignant melanoma, familial atypical mole and melanoma (FAMM) syndrome
Definition:Dysplastic nevus syndrome is a skin condition characterized by the presence of numerous atypical nevi, or moles.
Risk factors: White men and women with light-colored hair and freckled skin are believed to be at high risk for dysplastic nevi, especially with excessive sun exposure. Dysplastic nevi are strongly linked to melanoma: The presence of the former may signify an increased risk for developing the latter. Individuals with a family history of dysplastic nevi, with numerous dysplastic nevi on their bodies, and with at least two family members diagnosed with melanoma, are almost certain to develop melanoma. This is called familial atypical mole and melanoma (FAMM) syndrome.
Etiology and the disease process: Dysplastic nevi are abnormally growing moles. Whether ultraviolet exposure plays a significant role in their development is still a subject for debate. Dysplastic nevi are, however, associated with frequent and severe sunburns, a family history of dysplastic nevi, and weakened immunity (for example, due to cancer chemotherapy).
Incidence: In the United States, dysplastic nevi are present in 2 to 5 percent of the white population. In other countries, such as Australia, New Zealand, Germany, and Sweden, dysplastic nevi are clinically diagnosed in as much as 18 percent of the adult white population. This condition rarely occurs in individuals of Middle Eastern, black, or Asian descent. No gender predilection exists; the condition may start manifesting as early as childhood.
Symptoms: Unlike common moles, atypical nevi are asymmetrical; have uneven shades of tan, brown, red, or pink; have irregular borders; and are greater than 5 millimeters in diameter. Atypical moles are frequently found on the back, chest, abdomen, scalp, arms, or legs, but they can sometimes arise on unexposed areas such as the breasts or buttocks.
Screening and diagnosis: A thorough examination of the patient’s skin surface and a detailed family history are important in screening for dysplastic nevi. An excisional biopsy and histological analysis of the tissue sample will differentiate between dysplastic nevi and malignant melanoma.
Treatment and therapy: There is no definitive treatment for dysplastic nevi. Surgical removal of dysplastic moles does not guarantee against the development of melanoma.
Prognosis, prevention, and outcomes: Individuals with dysplastic nevi syndrome should avoid prolonged sun exposure without sunscreen protection. Regular skin examinations will help monitor for any suspicious changes in dysplastic nevi.