良性甲下黑色素细胞病变和早期甲下黑色素瘤 (SUM) 病变之间的区别仍然是诊断挑战。我们评估了 SUM 中阵列比较基因组杂交 (aCGH) 检测全基因组拷贝数变异 (CNV) 以及靶向下一代测序 (NGS) 的常规诊断效用。这项回顾性研究包括 20 例原位 SUM 和侵入性SUM 11例。 aCGH 分析检测到，除了 1 例侵入性 SUM 病例（n = 10）外，所有原位 SUM 病例中均存在常见癌基因扩增，且黑素细胞计数 (MC) >45/mm（n = 4 真阳性）和平均数量CNV为8.5。由于缺乏足够的黑素细胞进行分析（中位 MC 为 35.35；范围：10.16-39.5），剩余 13 例原位 SUM 给出假阴性结果（n = 13）。由于 DNA 量不足，有 4 例（3 例原位 SUM 和 1 例侵入式 SUM）分子分析失败。在整个队列中，aCGH 的敏感性为 52%，但当将截止值调整为 MC >45/mm 时，敏感性为 93%。在我们的 SUM 系列中，靶向 NGS 的信息量低于 aCGH 分析。为了区分恶性和良性病变，特别是原位 SUM 与非典型雀斑黑素细胞增殖，当 MC 高于每线性毫米 45 个黑素细胞时，应进行 aCGH 分析。这种泛基因组方法可以检测癌基因扩增，以及大量CNV >3，有力地支持了恶性肿瘤的诊断。© 2024 John Wiley

The distinction between the benign subungual melanocytic lesions and an early lesion of subungual melanoma (SUM) remains a diagnostic challenge. We evaluated the routine diagnostic utility of array Comparative Genomic Hybridization (aCGH) to detect whole-genome copy number variations (CNV) as well as targeted next-generation sequencing (NGS) in SUM.This retrospective study included 20 cases of in situ SUM and 11 cases of invasive SUM. Analysis by aCGH detected common oncogene amplifications in all but one case of invasive SUM (n = 10) and in all cases of in situ SUM with a melanocyte count (MC) >45/mm (n = 4 true positive) and the average number of CNV was 8.5. Thirteen remaining cases of in situ SUM gave false negative results (n = 13), owing to a lack of sufficient melanocytes to analyse (median MC of 35.35; range: 10.16-39.5). Molecular analysis failed in four cases (three in situ SUM and one invasive SUM) due to insufficient amounts of DNA. Across the whole cohort, the sensitivity of aCGH was 52%, but when adjusting the cutoff to MC >45/mm, the sensitivity was 93%. Targeted NGS was less informative than aCGH analyses in our series of SUM.To distinguish malignant from benign lesions, especially in situ SUM versus atypical lentiginous melanocytic proliferations, aCGH analysis should be performed when the MC is above 45 melanocytes per linear millimetre. This pangenomic method can detect oncogene amplifications, as well as a number of CNV >3, which strongly support the diagnosis of malignancy.© 2024 John Wiley & Sons Ltd.