Treatment of melanocytic nevi

Pigmented nevi are a heterogeneous group of lesions that range from uniquely curable with laser treatment, to partially responsive, to unresponsive or dangerous. This article presents laser and IPL treatment strategies from a clinical perspective for nevi organized by their typical responsiveness. A rationale for surgical excision, laser, and/or medical therapy in individual patients is also presented. Despite significant recent progress, it is clear that much understanding are still lacking about optimal laser treatment for pigmented lesions.     

Common acquired melanocytic nevi, dysplastic melanocytic nevi and malignant melanomas: an image analysis cytometric study

We used computerized image analysis cytometry in analyze 10 melanocytic lesions from each of the following categories: common acquired nevi, melanocytic nevi with architectural features of dysplasia, dysplastic melanocytic nevi (DMN) with slight atypia, DMN with moderate atypia, DMN with severe atypia, and superficial spreading melanomas. The nuclei of at least 50 consecutive nevomelanocytes in the most atypical zones were digitized at ×1000 under oil immersion, without knowledge of diagnosis by one observer. Grading of atypia was based on current practices as described in the literature. The results showed significant differences ( p < 0.05) in nuclear area and standard deviation of nuclear area between melanoma and DMN with severe atypia, and between DMN with severe atypia and all other categories of nevi. There were no differences among any lesions with respect to nuclear shape. No differences in nuclear area were found among DMN with moderate, or slight atypia, nevi with features of dysplasia, and typical nevi. These results show for the first time objective distinction of low-grade (slight-moderate atypia), and high-grade or severe atypia in pre-malignant nevomelanocytic lesions of the skin.     

Mitoses in conventional melanocytic nevi

Given that nevi may grow in size, mitotic figures may be expected in melanocytic nevi. We reviewed the literature for studies addressing this issue. We sought to determine the number of mitotic figures we might discover upon review of a group of randomly collected, conventional nevi. We reviewed 157 nevi from patients and found seven nevi exhibiting mitotic figures, comprising 4% of our sample. We noted the location of the mitoses within the nevi, the presence of any congenital features, as well as other features such as signs of inflammation or irritation. Through this study we have shown that occasional mitoses occur within unremarkable, conventional nevi.     

Halo eczema in melanocytic nevi

A case of halo eczema in melanocytic nevi is reported. Immunohistochemical techniques using monoclonal antibodies distinguished this condition from halo nevus. The lack of the expression of interleukin 2 receptor by T lymphocytes in the infiltrate suggest that the process is probably different from that of the allergic contact dermatitis.     

Multiple perineuriomatous melanocytic nevi

Perineuriomatous differentiation in solitary cutaneous melanocytic nevi has been described. We present an unusual case of a patient with multiple such perineuriomatous nevi. This presentation raises the possibility that a germline mutation may be responsible for the pathogenesis of these unusual lesions.     

Assessment of clonality in melanocytic nevi

BACKGROUND: Melanocytic nevi are among the most common lesions in man; however; their pathogenesis remains largely unknown. While often held to be neoplastic, this hypothesis has not been conclusively verified. Alternatively, some authorities have held that melanocytic nevi are hamartomas. More practically, difficulty may be encountered in the histologic discrimination of melanocytic nevi from melanoma. It was reported that nevi may be differentiated from melanoma in females by polymerase chain reaction (PCR) analysis of loci of human androgen receptor gene on the X-chromosome. However, contradictory findings have also been reported, suggesting that both acquired nevi and melanoma are clonal. METHODS: Fifteen examples of melanocytic nevus were analyzed via PCR for pattern of X-chromosome inactivation as indicated by the methylation status of the human androgen receptor gene. RESULTS: Among 15 nevi analyzed, 11 cases provided informative polymorphism at the androgen receptor loci. Nine of these 11 cases revealed a non-random pattern of X-chromosome inactivation. CONCLUSIONS: These findings suggest that melanocytic nevi are clonal/neoplastic lesions. As such, they cannot be discriminated from melanoma on the basis of clonality.     

Evolution of melanocytic nevi on the faces and necks of adolescents: a 4 y longitudinal study

All melanocytic nevi on the faces and necks of a cohort of students, initially aged 12-14 y, were mapped and photographed annually for 4 y. The features of each nevus were charted yearly noting changes in size and profile, and the appearance or disappearance of any nevi on a student's face and neck was recorded. Nevi were classified by size (small, < 2 mm; medium, 2-5 mm; large, > 5 mm), and by profile (flat, raised). Data from 20 adolescents selected randomly from the cohort for detailed analysis showed males had about twice as many nevi as females, but there was little difference between sexes in their patterns of nevus development. Approximately half the nevi were small in all years; under 5% were large. Over the 4 y of follow-up the proportion of flat nevi dropped from 70% to 57%, whereas nevus numbers increased by 47% in year 1, with smaller increases in older students. Most new or disappearing nevi were small and flat, although both incident and disappearing nevi could be larger and/or raised. Of the existing nevi that altered in the follow-up period, the tendency was towards an increase in size among raised but not among flat nevi; a lowering of profile among small nevi; and a raising of profile among larger nevi; but there were many exceptions to this pattern. Among several host factors examined, inability to tan after sun exposure was found to be significantly negatively associated with the propensity of nevi to change size over the study period. Overall our findings indicate that, contrary to conventional belief, there is a measurable turnover among melanocytic nevi even in early life.     

Dermoscopy of congenital melanocytic nevi: a ten-year follow-up study and comparative analysis with acquired melanocytic nevi arising in prepubertal age

Background

Dermoscopic characteristics of congenital melanocytic nevi (CMN) have been reported, however, dermoscopic variation during long-term follow-up and direct comparative analyses with acquired melanocytic nevi (AMN) are poorly documented.

Objectives

To assess dermoscopic changes of CMN (including lesions present at birth or appearing within the first two years of age) after a long-term period and evaluate possible dermoscopic differences withAMNarising during prepubertal age.

Materials & methods

We re-analysed clinical and dermoscopic features of CMN, investigated ten years earlier. New findings were compared with those previously recorded, as well as with those of AMNappearing before puberty in the same group of patients.

Results

In total, 493 lesions (86 CMN and 407 AMN) from 71 patients were examined. Except for a greater size (median area: 73.9 vs 22.8 mm²; p<0.001) and higher prevalence of hair (17.4% vs 4.7; p<0.001) in CMN, no significant difference was observed between the two cohorts, including global/local dermoscopic features (p>0.05). The follow-up of CMN revealed that dermoscopic pattern changed in only four lesions (4.7%) (from globular to globular-reticular or reticular) after ten years, though lesions with a globular architecture presented several “local” changes, namely an increase in circumscribed reticular areas (from 20.0% to 41.5%; p = 0.030), irregularly distributed globules (from 15.6% to 34.1%; p = 0.045), and large globules (from 46.7% to 68.3%; p = 0.043).

Conclusion

The dermoscopic appearance ofCMNis significantly stable during childhood and is similar to that of AMN arising before puberty, thus supporting a possible link between such types of nevi.

     

黑素细胞痣的形成机制

黑素细胞痣临床常见,通过对发疹性黑素细胞痣与免疫抑制剂的关系分析,认为黑素细胞痣的产生与免疫抑制有关.促黑素细胞激素-α能促进黑素细胞的增殖,在黑素细胞痣形成中发挥作用.其可通过环磷腺苷途径上调小眼畸形相关转录因子的表达,促进黑素细胞的增殖.促黑素细胞激素-α和免疫抑制剂影响朗格汉斯细胞、T细胞及IL-10、IL-12等细胞因子,可能作用于促分裂原激活蛋白激酶信号通路,上调小眼畸形相关转录因子的表达,从而导致黑素细胞痣的形成.