But that's exactly what a group of scientists from the Netherlands believe. They said they have discovered a pair of previously overlooked glands that are hidden away in our skulls where the nasal cavity and the throat meet.
The discovery was "thrilling" but the authors were "a bit skeptical" at first, said the study's lead author Matthijs H. Valstar, a surgeon in the department of head and neck oncology and surgery at The Netherlands Cancer Institute.
"We thought it wasn't possible to discover this in 2020," Valstar said. "It's important it's replicated and it should be done with different series of patients. It's important to have confirmation of new medical findings."
The glands cannot be seen with conventional methods of medical imaging like ultrasound, CT scans (computerized topography) or MRI (magnetic resonance imaging), the study authors said.
The "unknown entity" was only identified when the doctors were using an advanced and new type of scan called PSMA PET/CT that has been used to detect the spread of prostate cancer
. PSMA PET is shorthand for prostate-specific membrane antigen imaging using positron emission tomography.
Salivary glands show up clearly on this highly sensitive kind of imaging.
"People have three sets of large salivary glands, but not there," said study author Wouter Vogel, a radiation oncologist at The Netherlands Cancer Institute, in a news statement in May
. "As far as we knew, the only salivary or mucous glands in the nasopharynx are microscopically small, and up to 1000 are evenly spread out throughout the mucosa. So, imagine our surprise when we found these."
Many great scientific discoveries "come as a surprise — an incidental finding," said Joy Reidenberg, a professor of anatomy at the Icahn School of Medicine at Mount Sinai in New York City, who wasn't involved in the study.
"Luckily, these researchers were tuned into the data, and were anatomically savvy enough to note the unusual brightness in a region that was not thought to contain any salivary glands," Reidenberg added via email. "As the famous (late French biologist) Louis Pasteur once said: 'Chance favors the prepared mind.'"
It was a matter of debate whether the tubarial glands were a completely new organ or could be considered part of the salivary gland organ system, the study added.
"These findings support the identification of the tubarial glands as a new anatomical and functional entity," said the study
, which published in the journal Radiotherapy and Oncology.
The glands could be newly discovered, "but it is difficult to exclude that these might represent groups of minor salivary glands," said Dr. Valerie Fitzhugh, the interim chair of pathology at Rutgers New Jersey Medical School and Rutgers Robert Wood Johnson Medical School. Fitzhugh wasn't involved in the study.
Because the study concentrated on a small number of patients who were mostly male and used specific rather than standard tests, she added, examination of more women and healthier patients would allow for better data.
Overall, there is "still much to learn about the human body," Fitzhugh said, "and technology is allowing us to make these discoveries. This might be the first of some exciting discoveries within the body."
No matter how the glands are described, the authors said their discovery had clinical implications, especially for patients with head and neck cancer, including tumors in the throat or tongue. Radiotherapy can damage salivary glands, which can lead to dry mouth and trouble swallowing, speaking and eating.
"For most patients, it should technically be possible to avoid delivering radiation to this newly discovered location of the salivary gland system in the same way we try to spare known glands," Vogel said.
"Our next step is to find out how we can best spare these new glands and in which patients. If we can do this, patients may experience less side effects which will benefit their overall quality of life after treatment."