Background

Longitudinal melanonychia (LM) is a common finding in clinical practice; however, it has a broad differential diagnosis, including subungual melanoma (SUM), which can be difficult to distinguish clinically from benign conditions.

Objective

To identify clinical and dermoscopic features that distinguish histopathologically diagnosed SUM from benign LM and to evaluate the validity of the ABCDEF criteria among patients on whom a biopsy was performed.

Methods

Retrospective cohort study of consecutive patients who underwent nail matrix biopsy for LM at a single center from January 2011 to November 2017.

Results

A total of 84 cases in which biopsy was performed (8 cases of SUM and 76 benign) were included in the analysis. The patients with SUM were younger (P = .011), had their melanonychia longer (P = .017), and presented with a wider band (P = .002) and greater width percentage (P < .001) than patients with benign LM did. The number of ABCDEF criteria met did not differ between the groups.

Limitations

Retrospective single-center study; patients who did not undergo biopsy could not be studied.

Conclusions

In the cases of LM in which biopsy was performed, SUM usually presented with a wider band and greater width percentage than benign LM did. The number of ABCDEF criteria met was not different between the groups. Because many of the clinical and dermoscopic signs were less consistent, biopsy should be performed in cases with any concerning band, especially in those with width percentage higher than 40%.

中文翻译：

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回顾性单中心研究，评估纵向黑色素沉着症的临床和皮肤镜特征，ABCDEF标准以及恶性肿瘤的风险

背景

纵向黑色素症（LM）是临床实践中的常见发现；但是，它具有广泛的鉴别诊断，包括颌下黑色素瘤（SUM），在临床上很难将其与良性疾病区分开。

客观的

以确定将组织病理学诊断的SUM与良性LM区别开的临床和皮肤镜特征，并评估在进行活检的患者中ABCDEF标准的有效性。

方法

回顾性队列研究于2011年1月至2017年11月在单个中心对LM进行指甲基质活检的连续患者。

结果

分析中总共进行了84例活检（8例SUM和76例良性）。SUM患者比 良性患者更年轻（P = .011），黑色素瘤更长（P  = .017）且呈现出更宽的谱带（P  = .002）和更大的宽度百分比（P  <.001）。 LM做到了。两组之间符合ABCDEF标准的数量没有差异。

局限性

回顾性单中心研究；未进行活检的患者无法进行研究。

结论

在进行活检的LM病例中，SUM通常比良性LM表现出更宽的频带和更大的宽度百分比。两组之间符合ABCDEF标准的数量没有差异。由于许多临床和皮肤镜检查的体征不那么一致，因此，在有任何相关带的情况下，尤其是在宽度百分比高于40％的情况下，应进行活检。