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Topical Aluminum Chloride and Monsel's Solution Block Toluidine Blue Staining in Mohs Frozen Sections: Mechanism and
Curtis L Chen1, Steven Wilson2, Reza Afzalneia2
1Miller School of Medicine, University of Miami, Miami, Florida.
Background:
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.
Objective:
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.
Materials And Methods:
Leftover Mohs frozen sections and specimens were treated with aluminum chloride or Monsel's solution and processed with routine Mohs histology.
Results:
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.
Conclusion:
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.
Insights
A novel staining artifact in Mohs frozen sections, caused by hemostatic agents like aluminum chloride and Monsel's solution, can be prevented or corrected using ethylenediaminetetraacetic acid (EDTA) washes.
Area of Science:
- Dermatopathology
- Histotechnology
- Mohs Surgery
Background:
- A diminished-staining artifact in toluidine blue (T-blue) stained Mohs frozen sections, potentially impacting surgical accuracy, has been observed.
- This artifact, previously undescribed, is hypothesized to be caused by topical hemostatic agents.
Purpose of the Study:
- To investigate aluminum chloride and Monsel's solution as causes of the nonstaining artifact.
- To elucidate the mechanism behind this phenomenon.
- To develop preventative and corrective measures for the artifact.
Main Methods:
- Ex vivo skin specimens were treated with aluminum chloride or Monsel's solution and processed using routine Mohs histology.
- Ethylenediaminetetraacetic acid (EDTA) was used to test for reversal of the staining blockage.
Main Results:
- The nonstaining artifact was successfully reproduced in treated skin specimens.
- EDTA treatment reversed the T-blue staining blockage, indicating cation interference.
- Prussian blue staining confirmed direct binding of ferric cations to tissue sections.
Conclusions:
- Topical hemostatic agents containing aluminum or ferric cations cause T-blue staining artifacts in Mohs frozen sections.
- Pre-staining washes with EDTA can prevent this artifact.
- EDTA application and restaining can correct existing artifacts.