Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA.
J Cutan Pathol. 2023 Mar;50(3):247-258. doi: 10.1111/cup.14373. Epub 2022 Dec 21.
Melanocytic nevi existing in lymph nodes create a diagnostic challenge by mimicking metastases. PReferentially expressed Antigen in MElanoma (PRAME) immunohistochemical (IHC) stain can differentiate one from another. FLI-1 IHC expression has been shown in malignant melanoma with variable sensitivity while melanocytic nevi were reported to be negative. We hypothesized that FLI-1/Melan-A dual IHC staining may be used in the distinction of metastatic melanoma from nodal nevi and can be an alternative and/or complementary to PRAME. In this study, we examined 13 lymph nodes with metastatic melanoma and 13 lymph nodes with benign deposits. We stained all of the lymph nodes with FLI-1, FLI-1/Melan-A dual, and PRAME IHC stains. In addition, we stained paired skin samples of the metastatic lymph nodes with FLI-1 and PRAME. In primary cutaneous melanomas, 11 of 13 were positive for FLI-1 and PRAME expression (85%). Malignant cells in 12 and 13 lymph nodes showed positive expression of PRAME and FLI-1, respectively. Only one case with a nevic cell deposit was weakly positive for FLI-1 and the remaining benign cases were negative for both FLI-1 and PRAME. Our results show that FLI-1/Melan-A dual stain is as sensitive and specific as PRAME in distinguishing lymph nodes with metastatic melanoma from nodal nevi. Further studies with larger case numbers are needed to support our significant results.
存在于淋巴结中的黑色素细胞痣通过模拟转移来制造诊断上的挑战。优先表达的黑色素瘤抗原(PRAME)免疫组化(IHC)染色可以将两者区分开来。已经显示 FLI-1 在恶性黑色素瘤中的表达具有可变的敏感性,而黑色素细胞痣被报道为阴性。我们假设 FLI-1/Melan-A 双重 IHC 染色可用于区分转移性黑色素瘤与淋巴结痣,并可作为 PRAME 的替代物和/或补充物。在这项研究中,我们检查了 13 个有转移性黑色素瘤的淋巴结和 13 个有良性沉积物的淋巴结。我们用 FLI-1、FLI-1/Melan-A 双重和 PRAME IHC 染色对所有淋巴结进行了染色。此外,我们对转移性淋巴结的配对皮肤样本进行了 FLI-1 和 PRAME 染色。在原发性皮肤黑色素瘤中,13 例中有 11 例(85%)FLI-1 和 PRAME 表达阳性。12 个和 13 个淋巴结中的恶性细胞分别显示 PRAME 和 FLI-1 的阳性表达。只有一个含有痣细胞沉积物的病例 FLI-1 弱阳性,其余良性病例均为 FLI-1 和 PRAME 阴性。我们的结果表明,FLI-1/Melan-A 双重染色在区分转移性黑色素瘤淋巴结与淋巴结痣方面与 PRAME 一样敏感和特异。需要进一步的研究,以支持我们的重要结果。