Miller School of Medicine, University of Miami, Miami, Florida.
Mohs Surgery Unit and.
Dermatol Surg. 2019 Aug;45(8):1019-1025. doi: 10.1097/DSS.0000000000001761.
A diminished-staining artifact is observed in some Mohs frozen sections that are stained in toluidine blue (T-blue). Such an artifact, not yet described in the literature, may interfere with a Mohs surgeon's accurate reading. The authors hypothesize that topical hemostatic agents, aluminum chloride, and Monsel's solution are the causative factors.
To evaluate the aforementioned topical hemostatic agents as a potential cause of the nonstaining artifact, to propose the mechanism associated with this phenomenon, and to develop a method to prevent or rectify the problem.
Leftover Mohs frozen sections and specimens were treated with aluminum chloride or Monsel's solution and processed with routine Mohs histology.
Nonstaining artifact is reproduced in aluminum chloride or Monsel's solution-treated ex vivo skin specimens. The authors found that ethylenediaminetetraacetic acid (EDTA), a chelating agent, can reverse the staining blockage. Such a finding suggests that aluminum or ferric cations bind to tissue and subsequently inhibit T-blue from interacting with the tissue. Direct binding of ferric cations to the tissue section is demonstrated with Prussian blue iron staining.
By rinsing Mohs frozen sections in an EDTA solution before T-blue staining, the authors could prevent hemostatic agent-induced nonstaining. Applying an EDTA wash and restaining the slides can correct the same artifact.
在使用甲苯胺蓝（T-蓝色）染色的一些莫氏冷冻切片中观察到染色减弱的伪影。这种伪影尚未在文献中描述，可能会干扰莫氏外科医生的准确读数。作者假设局部止血剂、氯化铝和蒙氏溶液是导致这种伪影的原因。
评估上述局部止血剂是否可能是导致非染色伪影的原因，提出与这种现象相关的机制，并开发一种预防或纠正该问题的方法。
用氯化铝或蒙氏溶液处理剩余的莫氏冷冻切片和标本，并进行常规莫氏组织学处理。
在经氯化铝或蒙氏溶液处理的离体皮肤标本中重现了非染色伪影。作者发现，乙二胺四乙酸（EDTA），一种螯合剂，可以逆转染色阻塞。这一发现表明，铝或三价铁阳离子与组织结合，随后抑制 T-蓝色与组织相互作用。用普鲁士蓝铁染色直接证明了三价铁阳离子与组织切片的结合。
通过在 T-蓝色染色前用 EDTA 溶液冲洗莫氏冷冻切片，作者可以防止止血剂引起的非染色。应用 EDTA 冲洗并重新染色载玻片可以纠正相同的伪影。
