A comprehensive analysis of the tubarial glands

The tubarial glands (TGs) are a collection of salivary glands (SGs) located within the nasopharynx, proximal to the eustachian tube. Currently, there is no quantitative characterization of the TGs. We investigated the histological architecture of the TGs and compared it with the major and minor SGs for categorization. Tubarial, parotid, submandibular, sublingual, buccal, labial, and lingual glands were excised from human donors (8 male and 3 female). Hematoxylin and eosin-stained tissue sections were analyzed to measure the area of the largest lobule, number of ducts, number of mucinous acini, and mean mucinous acini area. Based on our observation, the TGs' histology resembles the minor SGs, while having some unique characteristics that distinguish them from both major and minor SGs. The area of the largest lobule in the TGs and minor SGs was smaller than the major SGs. TGs have a lower number of ducts than the major and minor SGs. TGs contain densely packed clusters of predominantly mucinous acini surrounded by loose connective tissue resembling minor SGs. This density may explain their previously observed high prostate-specific membrane antigen uptake. In our cohort of donors, sex-based differences were observed in the mean mucinous acini area between male and female TGs, submandibular and sublingual glands. Taken together, our findings suggest the histological characteristics of all SGs are better organized on a spectrum rather than discrete groups (major vs. minor) and provide information to open new avenues for research into the TGs' role in head and neck pathologies and sexual dimorphism of the SGs.