Modified Cajal's trichrome stain as a diagnostic aid in the study of epithelial pathology

Background: Diagnosis of initial epithelial pathology maybe difficult in Squamous Cell Carcinoma (SCC), Carcinoma In Situ and other atypical epithelial malignancies, under routine Haematoxylin and Eosin (H and E) stain. The detection of minor basement membrane alterations in doubtful cases is both time consuming and confusing. Aims: To evaluate efficacy of Modified Cajal's Trichrome Stain (CTS) in relation to Haematoxylin and Eosin for study of epithelial dysplasia, carcinoma in situ, micro invasive SCC, frank SCC, and SCC in lymph nodes. Materials and Methods: Formalin-fixed, paraffin-embedded tissue blocks of mild epithelial dysplasia (n = 2), moderate epithelial dysplasia (n = 2), severe epithelial dysplasia (n = 4), carcinoma in situ (n = 1), micro-invasive SCC (n = 4), verrucous carcinoma (n = 1), and frank OSCC (n = 5) were stained with CTS and H&E. The sections were compared based on set histopathological criteria. Results and Conclusion: In SCC cases stained with CTS, invasion into connective tissue and keratin pearls were strikingly evident. Depth of invasion could be more accurately determined. Tumour cells in lymph node were intensely contrasted and easily discernible. Thus, CTS is a good differential stain, clearly delineating the epithelial elements from the connective tissue elements visually. This helps in tracing the basement membrane very clearly. It is an economic, rapid and easy to use method which cannot replace Haematoxylin and Eosin stain in cancer diagnosis, but can definitely be used adjunctive to it. Prompt diagnosis is crucial to effective treatment, and this stain assists in early and rapid diagnosis of cancer.