Clinicopathological features and prognosis of patients with de novo versus nevus-associated melanoma in Taiwan

Studies surveying melanomas associated with melanocytic nevi in Asia are rare. In this study, we examined whether nevus-associated melanomas differ from de novo melanomas in terms of their associations with clinical factors, histologic characteristics, and patient survival in Taiwan. Using data on cancer cases obtained from the Department of Pathology archives and the Cancer Registry of National Taiwan University Hospital, we conducted a retrospective analysis of 103 consecutive melanoma patients who were diagnosed between 2010 and 2015 and received follow-up through November 2016. Approximately 17.5% of the melanomas in question were associated with a nevus. In patients under 65 years of age, non-acral lentiginous melanomas were significantly associated with a higher percentage of nevus-associated melanomas. The superficial spreading subtype, younger patient age, thinner tumor, intermittent solar exposure, and early stage were significant predictors of a melanoma being histologically associated with a nevus. The appearance of a nevus associated with a melanoma predicted better recurrence-free survival compared with de novo melanomas. Although acral lentiginous melanomas (70.9%) constituted the most common histologic subtype, only 9.6% of the acral lentiginous melanomas were associated with a nevus. Furthermore, there was no statistically significant difference between the nevus-associated and de novo acral lentiginous melanomas with regard to clinicopathological factors and survival. In conclusion, nevus-associated melanomas were uncommon among acral lentiginous melanomas. Relatedly, because over half of all melanomas in Asians are acral lentiginous melanomas, Asians are less likely than Caucasians to have nevus-associated melanomas.

针对亚洲地区与黑素细胞痣（melanocytic nevi）相关的黑色素瘤（melanoma）的研究较为罕见。本研究旨在探讨台湾地区中，与痣相关的黑色素瘤在临床因素关联、组织学特征及患者生存情况方面，是否与新发黑色素瘤（de novo melanoma）存在差异。本研究依托台湾大学医院病理科档案及癌症登记处获取的癌症病例数据，对2010年至2015年间确诊、并随访至2016年11月的103例连续性黑色素瘤患者开展回顾性分析。本次纳入研究的黑色素瘤中，约17.5%与黑素细胞痣相关。在65岁以下患者群体中，非肢端雀斑样黑色素瘤（acral lentiginous melanoma）与痣相关黑色素瘤的占比显著更高。浅表扩散型亚型、患者年龄更轻、肿瘤厚度更薄、间歇性日光暴露以及疾病早期分期，均为黑色素瘤在组织学上与痣相关的显著预测因素。与新发黑色素瘤相比，伴痣的黑色素瘤患者的无复发生存期更优。尽管肢端雀斑样黑色素瘤占比达70.9%，为最常见的组织学亚型，但其中仅9.6%的病例与黑素细胞痣相关。进一步分析显示，伴痣与新发的肢端雀斑样黑色素瘤在临床病理特征及生存情况方面，均未呈现统计学显著性差异。综上，肢端雀斑样黑色素瘤中伴痣相关的病例较为少见。此外，由于亚洲人群中超过半数的黑色素瘤为肢端雀斑样黑色素瘤，因此亚洲人群罹患痣相关黑色素瘤的概率较白种人更低。