Histopathological evaluation of minor salivary gland aberrations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most established oral cancers in India, with high morbidity and mortality. The most common etiological agent associated with it is tobacco (in any form), which releases chemical carcinogens that affect not only the oral epithelial lining but also deep stromal structures such as minor salivary glands. They may cause changes in ductal or acinar part of gland depending on tumor grade, thus providing a fertile soil for tumor growth and recurrence.

To observe the frequency of minor salivary gland changes associated with tobacco as well as to measure the length and depth of ductal involvement in routine tissue sections of OED and OSCC.

A total of 94 hematoxylin and eosinstained archival slides which included cases of well, moderate, and poorly differentiated OSCC and oral epithelial dysplasia were histopathologically evaluated to observe changes in different components of minor salivary gland. Ductal hyperplasia, ductal metaplasia, mucous pooling within duct, acinar degeneration, pattern of malignant cell invasion (single/clusters), inflammatory infiltrate, eosinophilic cuffing around the gland, and glandular/vascular involvement were evaluated in each slide and correlated with different grades of OSCC.

Ductal hyperplasia, inflammatory cell infiltrate, mucous pooling, and pattern of malignant cell infiltration came out to be statistically significant with the highest percentage of changes being observed in poorly differentiated squamous cell carcinoma > moderately differentiated squamous cell carcinoma> well differentiated squamous cell carcinoma>oral epithelial dysplasia. Further, the results of this study suggest that extension of dysplasia or squamous cell carcinoma from overlying oral epithelium along salivary gland ducts is an uncommon finding. Conclusion: Hence, histopathological interpretation for OED and OSCC should also include changes related to associated minor salivary gland tissue as detection and eradication of the putative precursors are the best way of decreasing the overall morbidity caused by tumors.