Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA.
Departments of Pathology, Medical College of Wisconsin, Milwaukee, WI, USA.
Diagn Pathol. 2019 Jun 14;14(1):57. doi: 10.1186/s13000-019-0822-4.
Systemic amyloidosis is a devastating group of disorders for which there is no current cure. The treatment goal is to reduce the burden of amyloidogenic protein precursors. The treatment is only effective if applied early in the disease process before significant and irreversible end organ damage has taken place. Congo red is still the standard stain used in most histopathology laboratories to identify amyloid material in tissues. The identification of Congophilic amyloid material is challenging because of multiple interfering factors. Here we describe improved sensitivity of identifying Congophilic materials in histologic sections using a metallurgical polarized microscope specifically constructed for polarized microscopy. The microscope is equipped with strain-free optics, matching polarizers, dis-integrated compensators, and a circular mobile stage. Compared to a standard clinical microscope, this setup significantly improves sensitivity of identifying amyloid material in Congo red-stained slides. We also describe the deleterious effect of plastic coverslip which can interfere with the ability to examine the slides under polarized light. We present a series of 10 different patients who had cardiac, brain, and salivary gland biopsies that were either equivocal or deemed negative using a standard clinical microscope but were positive using the equipment described above. These samples were confirmed to be positive by other methods including electron microscopy. We conclude that use of the correct equipment is needed before ruling out amyloidosis in tissue sections.
系统性淀粉样变是一组破坏性疾病，目前尚无治愈方法。治疗目标是减少淀粉样蛋白前体的负担。治疗只有在疾病过程早期应用，在发生明显和不可逆转的终末器官损伤之前才有效。刚果红仍然是大多数组织病理学实验室用于识别组织中淀粉样物质的标准染色剂。由于存在多种干扰因素，识别刚果红阳性的淀粉样物质具有挑战性。在这里，我们描述了使用专门为偏光显微镜构建的冶金偏光显微镜在组织切片中识别刚果红阳性物质的敏感性的提高。该显微镜配备了无应变光学器件、匹配的偏振器、分解补偿器和圆形移动台。与标准临床显微镜相比，这种设置显著提高了识别刚果红染色载玻片上淀粉样物质的敏感性。我们还描述了塑料盖玻片的有害影响，它会干扰在偏光下检查载玻片的能力。我们介绍了 10 例不同的患者，他们的心脏、大脑和唾液腺活检在使用标准临床显微镜时结果不确定或被认为是阴性的，但使用上述设备时结果是阳性的。这些样本通过包括电子显微镜在内的其他方法被证实为阳性。我们得出结论，在排除组织切片中的淀粉样变性之前，需要使用正确的设备。
