Melanocytic nevus pathophysiology
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Editors-In-Chief: Martin I. Newman, M.D., FACS, Cleveland Clinic Florida, [1];Associate Editor(s)-in-Chief: Qurrat-ul-ain Abid, M.D.[2] Michel C. Samson, M.D., FRCSC, FACS [3]
Overview
Melanocytic nevus is a benign growth on the skin (usually tan, brown, or flesh-colored) that contains a cluster of melanocytes and surrounding supportive tissue.
Pathophysiology
Congenital melanocytic nevi (CMN)
- When melanocytic nevi are present at birth or within the first few months of life they are known as Congenital melanocytic nevi (CMN).
- Congenital melanocytic nevi (CMN) are hamartomas lesions.
- Small melanocytic nevi that appear during early childhood between three months and two years of age, resemble true CMN clinicaly and histologicaly and are known as "tardive CMN," "early-onset nevi," and "congenital nevus-like nevi.[1]
- During embryogenesis clonal proliferations of benign melanocytes may give rise to melanocytic nevi.[2][3]
- BRAF V600E mutations have a very high corelation with small congenital melanocytic nevi (CMN), acquired melanocytic nevi and cutaneous melanomas.[4][5]
- While giant congenital melanocytic nevi (CMN) have somatic gain-of-function mutations in NRAS.[6][7]
- Compared to acquired melanocytic nevi, CMN penetrate into deeper layers of dermis.[8]
- Melanocytes in CMN follow pathyway of nerves and vessels and grow along adenxal structures (eg, hair follicles, sebaceous glands, eccrine ducts) and settle between collagen bundles in a single arrangement.[9][10]
Gross Pathology
References
- ↑ Makkar HS, Frieden IJ (August 2002). "Congenital melanocytic nevi: an update for the pediatrician". Curr. Opin. Pediatr. 14 (4): 397–403. PMID 12130901.
- ↑ Tannous ZS, Mihm MC, Sober AJ, Duncan LM (February 2005). "Congenital melanocytic nevi: clinical and histopathologic features, risk of melanoma, and clinical management". J. Am. Acad. Dermatol. 52 (2): 197–203. doi:10.1016/j.jaad.2004.07.020. PMID 15692463.
- ↑ Price HN, Schaffer JV (2010). "Congenital melanocytic nevi-when to worry and how to treat: Facts and controversies". Clin. Dermatol. 28 (3): 293–302. doi:10.1016/j.clindermatol.2010.04.004. PMID 20541682.
- ↑ Ichii-Nakato N, Takata M, Takayanagi S, Takashima S, Lin J, Murata H, Fujimoto A, Hatta N, Saida T (September 2006). "High frequency of BRAFV600E mutation in acquired nevi and small congenital nevi, but low frequency of mutation in medium-sized congenital nevi". J. Invest. Dermatol. 126 (9): 2111–8. doi:10.1038/sj.jid.5700366. PMID 16691193.
- ↑ Wu J, Rosenbaum E, Begum S, Westra WH (December 2007). "Distribution of BRAF T1799A(V600E) mutations across various types of benign nevi: implications for melanocytic tumorigenesis". Am J Dermatopathol. 29 (6): 534–7. doi:10.1097/DAD.0b013e3181584950. PMID 18032947.
- ↑ Dessars B, De Raeve LE, Morandini R, Lefort A, El Housni H, Ghanem GE, Van den Eynde BJ, Ma W, Roseeuw D, Vassart G, Libert F, Heimann P (January 2009). "Genotypic and gene expression studies in congenital melanocytic nevi: insight into initial steps of melanotumorigenesis". J. Invest. Dermatol. 129 (1): 139–47. doi:10.1038/jid.2008.203. PMID 18633438.
- ↑ Charbel C, Fontaine RH, Malouf GG, Picard A, Kadlub N, El-Murr N, How-Kit A, Su X, Coulomb-L'Hermine A, Tost J, Mourah S, Aractingi S, Guégan S (April 2014). "NRAS mutation is the sole recurrent somatic mutation in large congenital melanocytic nevi". J. Invest. Dermatol. 134 (4): 1067–1074. doi:10.1038/jid.2013.429. PMID 24129063.
- ↑ Mark GJ, Mihm MC, Liteplo MG, Reed RJ, Clark WH (September 1973). "Congenital melanocytic nevi of the small and garment type. Clinical, histologic, and ultrastructural studies". Hum. Pathol. 4 (3): 395–418. PMID 4756859.
- ↑ "Precursors to malignant melanoma. National Institutes of Health Consensus Development Conference Statement, Oct. 24-26, 1983". J. Am. Acad. Dermatol. 10 (4): 683–8. April 1984. PMID 6715623.
- ↑ Kokta V, Hung T, Al Dhaybi R, Lugassy C, Barnhill RL (April 2013). "High prevalence of angiotropism in congenital melanocytic nevi: an analysis of 53 cases". Am J Dermatopathol. 35 (2): 180–3. doi:10.1097/DAD.0b013e318260908c. PMID 22771898.