Dysplastic nevus

Classification according to ICD-10
D22.9	Dysplastic nevus
ICD-10 online (WHO version 2019)

Microphoto of a dysplastic nevus. HE staining .

A dysplastic nevus (also Clark's melanocytic nevus ) belongs to the pigmented and circumscribed malformations of the skin ( pigment nevi ), which are colloquially called " birthmarks " or " liver spots ". In contrast to the other such skin changes, which are made up of normal melanocytes or nevus cells , here there is an increase in atypical cells with an irregular appearance. The view that dysplastic nevi are the precursors of superficial spreading melanoma is controversial. However, 20–30% of melanomas also contain nevus cells, which suggests a transformation or progression from nevus to melanoma. Some smaller prospective studies confirm an increased risk of malignancy, at least for large nevi. On the other hand, 70% of melanomas develop de novo on normal skin and not from a pre-existing nevus. The number of Clark nevi can correlate with the melanoma risk even without direct transformation, due to the similarities in their etiology .

Epidemiology

In whites, dysplastic nevi occur with an average frequency of about 5%. However, there is no preference for age or gender. It also occurs more frequently in the presence of melanoma , familial melanoma and syndrome of dysplastic nevi (DNA). It is believed that over 20% of melanomas arise from such a syndrome.

clinic

Dysplastic nevi show a “more restless image” on the skin than normal nevus cell nevi . They have more shades (from dark brown to light red or depigmented) and are irregular or piebald in color. The boundaries of such dysplastic skin changes can be sharp, but mostly they are fuzzy, frayed edges. Dysplastic nevi are usually larger than 5 mm in diameter and may have minor raised areas, especially in the center.

Course and prognosis

The risk of degeneration is only insignificantly higher than that of normal skin. The fact that every Central European has between 5 and 10 Clark nevi on average, but the incidence of melanoma is only 10-15 / 100,000, supports this thesis.

therapy

Dysplastic nevi that are changing in any way or that are located in areas that the patient cannot regularly control should be surgically excised in order to be able to stop any further development into malignant melanoma . All other dysplastic nevi must be checked regularly depending on the individual risk and assessed by the dermatologist at regular intervals. Furthermore, excessive sun exposure should be avoided.

literature

Thomas B. Fitzpatrick, Klaus Wolff (ed.): Atlas and synopsis of clinical dermatology: common and threatening diseases . 3. Edition. McGraw-Hill, New York; Frankfurt a. M., 1998, ISBN 0-07-709988-5 .
Ernst G. Jung, Ingrid Moll (Ed.): Dermatology . 5th edition. Thieme, Stuttgart, 2003, ISBN 3-13-126685-6

Individual evidence

↑ RM Cymerman, Y. Shao et al. a .: De Novo vs Nevus-Associated Melanomas: Differences in Associations With Prognostic Indicators and Survival. In: Journal of the National Cancer Institute. Volume 108, number 10, October 2016, p., Doi : 10.1093 / jnci / djw121 , PMID 27235387 , PMC 5939856 (free full text).
^ EK Hale, J. Stein u. a .: Association of melanoma and neurocutaneous melanocytosis with large congenital melanocytic naevi - results from the NYU-LCMN registry. In: The British journal of dermatology. Volume 152, Number 3, March 2005, pp. 512-517, doi : 10.1111 / j.1365-2133.2005.06316.x , PMID 15787820 .
↑ CL Egan, SA Oliveria u. a .: Cutaneous melanoma risk and phenotypic changes in large congenital nevi: a follow-up study of 46 patients. In: Journal of the American Academy of Dermatology. Volume 39, Number 6, December 1998, pp. 923-932, PMID 9843003 .
^ AC Viana, EM Goulart et al. a .: A prospective study of patients with large congenital melanocytic nevi and the risk of melanoma. In: Anais brasileiros de dermatologia. Volume 92, number 2, 2017 Mar-Apr, pp. 200–205, doi : 10.1590 / abd1806-4841.20175176 , PMID 28538879 , PMC 5429105 (free full text).
↑ R. Pampena, A. Kyrgidis et al. a .: A meta-analysis of nevus-associated melanoma: Prevalence and practical implications. In: Journal of the American Academy of Dermatology. Volume 77, number 5, November 2017, pp. 938-945.e4, doi : 10.1016 / j.jaad.2017.06.149 , PMID 28864306 (review).

[PMID27235387-1] RM Cymerman, Y. Shao et al. a .: De Novo vs Nevus-Associated Melanomas: Differences in Associations With Prognostic Indicators and Survival. In: Journal of the National Cancer Institute. Volume 108, number 10, October 2016, p., Doi : 10.1093 / jnci / djw121 , PMID 27235387 , PMC 5939856 (free full text).

[PMID15787820-2] EK Hale, J. Stein u. a .: Association of melanoma and neurocutaneous melanocytosis with large congenital melanocytic naevi - results from the NYU-LCMN registry. In: The British journal of dermatology. Volume 152, Number 3, March 2005, pp. 512-517, doi : 10.1111 / j.1365-2133.2005.06316.x , PMID 15787820 .

[PMID9843003-3] CL Egan, SA Oliveria u. a .: Cutaneous melanoma risk and phenotypic changes in large congenital nevi: a follow-up study of 46 patients. In: Journal of the American Academy of Dermatology. Volume 39, Number 6, December 1998, pp. 923-932, PMID 9843003 .

[PMID28538879-4] AC Viana, EM Goulart et al. a .: A prospective study of patients with large congenital melanocytic nevi and the risk of melanoma. In: Anais brasileiros de dermatologia. Volume 92, number 2, 2017 Mar-Apr, pp. 200–205, doi : 10.1590 / abd1806-4841.20175176 , PMID 28538879 , PMC 5429105 (free full text).

[PMID28864306-5] R. Pampena, A. Kyrgidis et al. a .: A meta-analysis of nevus-associated melanoma: Prevalence and practical implications. In: Journal of the American Academy of Dermatology. Volume 77, number 5, November 2017, pp. 938-945.e4, doi : 10.1016 / j.jaad.2017.06.149 , PMID 28864306 (review).