Background: The aim of this study was to evaluate the accuracy of three combination staining approaches, each composed of pancytokeratin immunostaining with an elastic-fiber staining method of choice, in diagnosing visceral pleural invasion (VPI) in lung adenocarcinoma patients.
Methods: Tissue samples were resected from 23 lung adenocarcinoma patients, for whom neither hematoxylin and eosin nor Gomori’s aldehyde-fuchsin (GAF) staining accurately detected the presence of VPI. Three slices were prepared from each sample and examined by immunohistochemical staining of cytokeratin AE1/AE3 and one of the following methods for elastic-fiber staining, including Victoria blue (VB), GAF, or Weigert’s resorcin-fuchsin (WRF). The staining scores and slider view time were compared among the three staining protocols with tumor extension beyond the elastic layer of the visceral pleura as the diagnostic criterion for VPI.
Results: Conclusive diagnoses were achieved for all 23 tissue samples stained with VB, 18 with GAF, and 17 with WRF. VB staining was the fastest of the three methods, and produced significantly brighter, clearer color, and better contrast between the elastic fibers and tumor cells, thus facilitating slide review.
Conclusions: The combination of VB elastic fiber and cytokeratin AE1/AE3 staining is a user-friendly, fast, and highly effective method that produces bright stains, favorable color contrast against the background, and high tumor localization accuracy. Hence, this method can improve the accuracy of VPI diagnosis and the corresponding staging of lung adenocarcinoma. We recommend the combined use of VB and pancytokeratin immunostaining when VPI is suspected.