Qualitative analysis of keratin in oral squamous cell carcinoma using alcian blue-periodic acid schiff, Ayoub-Shklar, and modified papanicolaou as special stains.

Background: The morphological features of keratinisation can impact histopathological diagnosis. Routine haematoxylin and eosin (H&E) stain has its limitations in moderately differentiated cases of oral squamous cell carcinoma (OSCC).

Aims: The aim of this study was to evaluate and compare the characteristics of staining and identification of keratin by routine H&E stain, Alcian Blue-Periodic Acid Schiff (AB-PAS), Ayoub-Shklar, and Modified Papanicolaou (PAP) stain in OSCC cases.

Material and methods: Overall, 30 cases of OSCC were included in experimental groups, and 20 cases of well-differentiated squamous cell carcinoma (WDSCC) and ten cases of moderately differentiated squamous cell carcinoma (MDSCC) and ten cases of normal keratinised oral mucosa (NKOM) were included in the control group. Histopathologicaly diagnosed cases of OSCC were selected, and tissue sections from each were prepared. Fisher's exact test was used for the statistical analysis.

Results and conclusions: We observed that the staining intensity was greater in Ayoub-Shklar in WDSCC and in MDSCC followed by modified PAP and AB-PAS-stained sections and the staining specificity was greater in modified PAP in WDSCC and in MDSCC followed by AB-PAS and Ayoub-Shklar in stained sections. We conclude that special stains like AB-PAS, Ayoub-Shklar, and modified PAP stain can prove to be a simple solution to detect the presence and pattern of keratin histologically. The efficacy of distinct identification of keratin pearls and individual cell keratinisation in OSCC-modified PAP stain is better. It can be used as alternative stain to H&E for histological grading of OSCC based on keratinisation.