Introduction
The human body contains a pair of previously overlooked and clinically relevant macroscopic new bilateral salivary gland called “tubarial glands”, which were recently described in patients with cancer. The scientists from Netherlands Cancer Institute (NCI) while doing a routine screening of 100 prostate cancer patients using prostatic-specific membrane antigen (PSMA) positron-emission tomography/computed tomography scan accidentally found the presence of large masses of glandular tissue in human nasopharynx in all patients. This discovery was done due to prostate-specific membrane antigen ligands (PSMA PET/CT) in a nuclear medicine approach that bears high diagnostic accuracy for salivary glands and subsequently the finding was confirmed histologically in the cadavers. Thus, tubarial glands are described as being located between the throat and the nasal cavity, notably torus tubarius, from which they derive their name. The secretions of these glands are poured onto the dorsolateral wall of the nasopharynx and lubricate and moisten the upper part throat located behind the nose (nasopharynx) and behind the mouth (oropharynx). On an average, they are about 4 cm (1.5 inches) long and these glands were categorized as seromucous glands with ducts by histological histochemical studies.[Figure 1]
The surgical importance of these glands is during radiotherapy including the pharyngeal area of these glands, can lead to xerostomia and dysphagia, suggesting, first, a major functional role for these recently described organs, and second, a potential for averting these symptoms by avoiding radiotherapy/ radiation of this region.1
Tubarial Glands and Sjogren’s Syndrome
In a study, it was speculated that tubarial glands may be implicated in Sjogren’s syndrome (SS) and that might be the reason why some patients with SS present with upper airway dryness, ultimately leading to improve SS classification and diagnostic criteria. It was suggested that a multicenter PSMA PET/CT study of SS patients with or without a dry rhinopharynx could shed light into tubarial glands’ role in SS. If it were possible to anatomically access these glands and to conduct biopsies, one could confirm whether they are involved in SS or not too. In the former case, SS classification and diagnostic criteria might be reformed. 2
Controversies on Tubarial Salivary Glands
It remains to be seen if the glands are classified as minor or major salivary glands but the discovery of a new body structure in 2020 certainly sparks wide scientific interest. The tubarial glands exhibit several aspects analogous to the minor salivary glands of the palate, potentially suggesting a designation as minor rather than major glands for the region in question. The authors concede these resemblances, stating “the tubarial glands have many similarities with the palatal conglomerate of microscopic glands”. 3
The controversy about tubarial salivary glands begins with the location of the glands, which suggests that their fluids do not reach the mouth and that they are therefore not involved in the production of saliva, and due to the glands’ apparent lack of amylase, a key protein found in saliva, it was not appropriate to classify the tubarial glands as salivary glands at all. Another controversy was the gender disparity as 99 out of the 100 patients in the sample used to identify the tubarial glands were male. Because of this gender imbalance, it was thought that it will be important to conduct further analyses to determine if are any differences in these structures in females. There was again a controversy that this discovery of tubarial glands are not new as in the 19th century, anatomists Jean Cruveilhier and Jakob Henle and otologist Adam Politzer described glands in this region of the throat.
Importance in Oncology
The sparing of these glands during radiotherapy of head-and-neck cancer patients will relieve them from common posttherapy symptoms which is seen in many of the oncology patients like dryness of the mouth (xerostomia) and difficulty in swallowing (dysphagia). 4 There is a first case report which indicates that the "tubarial salivary gland", like the other large salivary glands in the head and neck area, can also develop malignant degeneration and may develop salivary gland carcinoma. 5
Conclusion
Tubarial salivary glands are the new kid on the block and must undergo several research to establish its place firmly in the annals of Anatomy. If the xerostomia and dysphagia can be prevented in every patient undergoing radiotherapy by saving radiation injury to these tubarial salivary gland, it will help in decreasing the morbidity and mortality significantly in such cancer patients in the future.
