Department of Dermatology, Dermatology Hospital, Southern Medical University, Guangzhou, China.
Department of Dermatology, Dermatology Hospital, Southern Medical University, Guangzhou, China,
Dermatology. 2022;238(2):368-376. doi: 10.1159/000518082. Epub 2021 Aug 26.
Quick and accurate diagnosis of primary cutaneous amyloidosis (PCA) may be difficult because its symptoms are often subtle and nonspecific.
We sought to review the literature on the roles of various staining methods in the diagnosis of amyloidosis and demonstrate added benefits of using rapid 4,6-diamidino-2-phenylindole (DAPI) staining in the diagnosis of PCA.
Three groups of cases, namely, PCA, neurodermatitis, and prurigo nodularis, were retrieved from a computerized pathology database for study, and their paraffin-embedded tissue blocks were cut following standard procedures. The tissue sections were stained with three stains: hematoxylin-eosin (HE), Congo red, and DAPI stains, and examined under the microscope to compare the staining patterns of these three methods. We also performed amyloid keratin and apolipoprotein E (APOE) staining on the sections of PCA in order to further support our conclusion. The PCA sections were read by junior and senior dermatopathologists for comparison.
The sensitivity of DAPI staining for PCA was significantly higher than that of Congo red staining and HE staining (p < 0.001). This statement holds true whether the experiment was grouped in one sample or was divided into groups of junior and senior dermatopathologists (p < 0.001). The DAPI-positive staining areas, except for the nuclei, were consistent with the amyloid deposition areas. In this study, DAPI staining had a sensitivity of 98.6% and a specificity of 100%.
DAPI staining could serve as a useful technique to establish the diagnosis of PCA, and its high efficacy in diagnosing PCA makes it less dependent on the experience levels of the evaluators. Additionally, the binding of DAPI to the A-T-rich sequence of double-stranded DNA suggests that amyloid may contain DNA or a similarly structured nucleic acid.
原发性皮肤淀粉样变性（PCA）的快速准确诊断可能具有挑战性，因为其症状通常较为微妙且非特异性。
我们旨在回顾各种染色方法在淀粉样变性诊断中的作用，并展示快速 4,6-二脒基-2-苯基吲哚（DAPI）染色在 PCA 诊断中的额外益处。
从计算机病理学数据库中检索了三组病例，即 PCA、神经炎和结节性痒疹，按标准程序对其石蜡包埋组织块进行切片。用三种染色剂（苏木精-伊红（HE）、刚果红和 DAPI）对组织切片进行染色，并在显微镜下观察比较这三种方法的染色模式。我们还对 PCA 切片进行了淀粉样蛋白角蛋白和载脂蛋白 E（APOE）染色，以进一步支持我们的结论。由初级和高级皮肤科病理学家对 PCA 切片进行阅读，然后进行比较。
DAPI 染色对 PCA 的敏感性明显高于刚果红染色和 HE 染色（p < 0.001）。无论实验是在一个样本中进行分组，还是分为初级和高级皮肤科病理学家的组，这一说法都是成立的（p < 0.001）。除了细胞核之外，DAPI 阳性染色区域与淀粉样沉积物区域一致。在这项研究中，DAPI 染色的敏感性为 98.6%，特异性为 100%。
DAPI 染色可作为一种有用的技术来确立 PCA 的诊断，其在诊断 PCA 方面的高效性使其对评估者的经验水平依赖性降低。此外，DAPI 与双链 DNA 的 A-T 富含序列的结合表明，淀粉样物质可能含有 DNA 或类似结构的核酸。
