Yuchen Hu¹, Yvonne Bogun¹

¹Anatomical Pathology, NSW Health Pathology, Prince of Wales Hospital, Randwick, NSW, Australia

Presence of malignant epithelial proliferations at resection margins indicates a positive margin and may have profound implications for patient management and outcomes. The true resection margins of the specimen are often inked at the time of cut-up, allowing reporting pathologists to correctly orient and designate the involved margin. Immunohistochemistry (IHC) is a useful technique to differentiate between malignant and benign processes in histology laboratories. However, it has been reported that ink colours may change after IHC processing^{1, 2}, leading to misinterpretation during reporting and potentially significant consequences for patient care. We hereby report a case in which the colour of the blue ink changed to black after IHC processing in a breast wide local excision specimen. We aim to highlight this potential pitfall, as it is crucial for pathologists to be aware of the colour change following IHC procedures. Risks can be mitigated by carefully comparing IHC slides with H&E-stained slides and selecting commercially available tissue-marking inks that are compatible with IHC kits and reagents.

References:

1.       Chaves Gomes, Deborah, and Gelareh Farshid. “Change of Blue Ink Margin Colour to Black in Immunohistochemistry Stained Slides: A Potential Pitfall for Pathology Cancer Margin Assessment.” Pathology, vol. 53, no. 4, June 2021, pp. 558–559, https://doi.org/10.1016/j.pathol.2020.08.025.

 

2.       Kiefer, Selina, et al. “Alteration of Tissue Marking Dyes Depends on Used Chromogen during Immunohistochemistry.” Cells, vol. 10, no. 4, 8 Apr. 2021, p. 835, https://doi.org/10.3390/cells10040835.

3.       Kim, So-Woon, et al. “Immunohistochemistry for Pathologists: Protocols, Pitfalls, and Tips.” Journal of Pathology and Translational Medicine, vol. 50, no. 6, 15 Nov. 2016, pp. 411–418.