salivary glands in mammals are exocrine glands (A gland that makes substances such as sweat, tears, saliva, milk, and digestive juices, and releases them through a duct or opening to a body surface) that produce saliva through a system of ducts. Humans have three paired major salivary glands (parotid, submandibular and sublingual) as well as hundreds of minor salivary glands. But, Researcher of the Netherland Cancer institute discovered a new location of the salivary glands during their work on prostate cancer, i.e. a new pair of salivary glands they published this news in the journal of Radiotherapy and Oncology last week. An unnoticed bilateral macroscopic emission tomography/computed tomography with prostate-specific membrane antigen ligand (PSMA PET/CT) used to explain the characteristics of this unknown object and its potential clinical implication for radiotherapy.

What they exactly found?

While finding the side effects of radiation on the head and neck were studying a new type of scan part of their research work, they found two “weird” areas the lit in the backside of nasopharynx. And their look very much similar to the major salivary glands.

Before we know that there are three major pair of salivary gland system in the human body and nearly more than 1000 minor salivary glands are labial and buccal gland, glossopalatine gland, and palatine and lingual glands like that present around the mucosa layer and help in tasting, mastication, swallowing, digestion and maintain a dental hygiene. When researchers looking at the scan (their research work) they found a bilateral structure in the back of the nasopharynx and they have a character of salivary glands.

The researcher put forward a name “tubarial glands” from their discovery. It is not clear right now if these glands will be classified as a major gland or it is a combination of minor glands, a separate organ, or a new part of an organ system

Research purposed this name based on their location as seen in other salivary glands like parotid, submandibular and sublingual they believe this would be the fourth pair of major salivary glands.

Why it is tough to discover this tubarial gland?

SALIVARY GLAND
fig: Conventional MRI of a person

Conventional imaging modes (ultrasound, CT, MRI) have never allowed to visualize this structure as it is poorly reachable because it is present under the base of skull and it interpretated as salivary gland never been possible. Its presence may have been visible in if we use retrospective evaluation (look back at work that were produced in past). But in these researchers used PSMA-PET/CT (positron emission tomography/computed tomography with prostate-specific membrane antigen ligand) in this total tracer uptake in the area of interest determined by visual comparison was on average similar to uptake in sublingual ligand as the area of interest also take this tracer so it was thought to have a similar characteristics like major salivary gland, and histology (the microscopic study, of the tissues of an animal or plant)

Function of this gland

It is hypothesized that it could contain a large number of seromucous acini (that secrete serous fluid) and therefore play a role in nasopharynx/oropharynx lubrication and swallowing.

Advantages of this findings

This could also be relevance in oncology as during treatment of head and neck cancer by high-dose external beam radiotherapy (RT) to salivary gland. Major salivary gland is often called organs at risk therefore having an extra pair of salivary glands can be helpful.

The next step could be finding out how to avoid this high dose radiotherapy toxicity to newly discovered glands so that patients experience less side effects and lead to a good life.

Reference:

Valstar, M.H., de Bakker, B.S., Steenbakkers, R.J., de Jong, K.H., Smit, L.A., Nulent, T.J.K., van Es, R.J., Hofland, I., de Keizer, B., Jasperse, B. and Balm, A.J., 2020. The tubarial salivary glands: A potential new organ at risk for radiotherapy. Radiotherapy and Oncology.

Photo Credit: https://www.nki.nl/

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