Chang Li-Wei, Kazlouskaya Viktoryia, Kazi Rashek, Davar Diwakar, Ferris Robert L, Ho Jonhan, Karunamurthy Arivarasan, Jedrych Jaroslaw J, Bunimovich Yuri L
Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA.
Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA; and.
Am J Dermatopathol. 2020 Nov;42(11):854-857. doi: 10.1097/DAD.0000000000001652.
Cutaneous melanomas may demonstrate a variety of histopathological features and genetic abnormalities. Melanomas that arise in the setting of blue nevi, also known as "malignant blue nevus" or melanoma ex blue nevus (MBN), share a similar histopathological and mutational profile with uveal melanoma. Most uveal melanomas show characteristic GNA11 or GNAQ mutations; additional BAP1 mutation or loss is associated with the highest risk of metastasis and worst prognosis. However, the significance of BAP1 loss in melanomas ex blue nevus remains unclear. We present a case of MBN arising from the scalp of a 21-year-old woman. The diagnosis was established on histopathological findings demonstrating a markedly atypical melanocytic proliferation with increased mitotic activity, necrosis, and a focus of angiolymphatic invasion. Immunohistochemical analysis demonstrated the absence of BAP1 nuclear expression within tumor cells. Next generation sequencing detected GNA11 Q209L mutation and BAP1 loss (chromosome 3p region loss), supporting the diagnosis. We reviewed another 21 MBN cases with reported BAP1 status from the literature. MBN with BAP1 loss presented at a younger average age (41 vs. 61 years), demonstrated larger average lesion thickness (9.0 vs. 7.3 mm), and had a higher rate of metastasis (50% vs. 33%) compared with BAP1-retained MBN. BAP1 expression studies may assist in the diagnosis and management of MBN, but further research is needed.
皮肤黑色素瘤可能表现出多种组织病理学特征和基因异常。起源于蓝色痣的黑色素瘤，也称为“恶性蓝色痣”或蓝色痣来源的黑色素瘤（MBN），与葡萄膜黑色素瘤具有相似的组织病理学和突变特征。大多数葡萄膜黑色素瘤显示特征性的GNA11或GNAQ突变；额外的BAP1突变或缺失与转移风险最高和预后最差相关。然而，BAP1缺失在蓝色痣来源的黑色素瘤中的意义仍不清楚。我们报告了一例发生在一名21岁女性头皮的MBN病例。根据组织病理学结果确诊，显示有明显的非典型黑素细胞增殖，有丝分裂活性增加、坏死以及一个血管淋巴管浸润灶。免疫组织化学分析显示肿瘤细胞内无BAP1核表达。二代测序检测到GNA11 Q209L突变和BAP1缺失（3号染色体p区域缺失），支持诊断。我们从文献中回顾了另外21例报告了BAP1状态的MBN病例。与保留BAP1的MBN相比，BAP1缺失的MBN平均发病年龄更小（41岁对61岁），平均病变厚度更大（9.0mm对7.3mm），转移率更高（50%对33%）。BAP1表达研究可能有助于MBN的诊断和管理，但仍需要进一步研究。
