Dysplastic nevus

A Dysplastic nevus ( melanocytic nevus also Clark shear ) is one of the pigmented and circumscribed malformation of the skin ( pigmented nevi ), which are colloquially called " birthmarks " or " liver spots". In contrast to other such skin lesions, which are composed of normal melanocytes or nevus cells, this will mean a proliferation of atypical cells with irregular appearance. The view that dysplastic nevi were precursors of superficial spreading melanoma is now regarded as obsolete, as this could be demonstrated in any prospective study. The majority of the melanoma arises de novo to normal skin and does not from a pre-existent nevus. However, the presence of several Clark naevi, moles can pose an increased risk of melanoma a character ( but not a reason ). This is due to the similarities in their etiology.

Epidemiology

In the White dysplastic nevi occur with an average frequency of about 5%. However, there is no preference for age or gender. High incidence also can be found in the presence of melanoma, the familial melanoma and dysplastic nevi in the syndrome (DNS). It is believed that over 20 % of melanomas arise in the bottom of such a syndrome.

Clinic

Dysplastic nevi show on the skin a " unruhigeres picture" than ordinary melanocytic nevi. They have more colors dyed ( from dark brown to bright red or depigmented ) and are irregular or piebald. The limitation of such dysplastic lesions can be sharp, but mostly it's blurry, jagged edges. Dysplastic nevi are usually greater than 5 mm in diameter, and raised portions can have a small extent, in particular in the center.

Course and prognosis

The risk of degeneration is only slightly higher than to set the normal skin. The fact that each Central Europeans have on average 5-10 Clark naevi, moles, melanoma incidence but only 10 - 15 / 100,000 is, supports this thesis.

Therapy

Dysplastic nevi that change in any way, or are in places that can not regularly check the patient should be surgically excised in order to intercept the possible evolution into a malignant melanoma definitely can. All other dysplastic nevi ever need to be checked regularly according to individual risk and examined at intervals by a dermatologist. Furthermore, excessive sun exposure should be avoided.