Given modern technology, one might assume we already know all parts of the human body. We’re taught at a young age that our skeleton comprises 206 bones. It stands to reason we can identify all the organs as well then, right?
In an incredible discovery earlier this month, researchers at the Netherlands Cancer Institute proved we don’t know as much as we thought we did. Using a very specific type of CT-based imaging, Wouter Vogel and Matthijs Valstar discovered a previously overlooked salivary gland way in the back of the nasopharynx.
The researchers were imaging 100 patients with prostate or urethral gland cancer using positron emission tomography/computed tomography with prostate-specific membrane antigen ligands (PSMA PET/CT) to examine the effects of radiation for these patients, as radiation therapy commonly damages salivary glands. As it turns out, the new prostate-specific membrane antigen-ligands were the key to the discovery.
The newly detected and named “tubarial glands” are flat structures at a poorly accessible anatomical location under the skull base—an area that can only be visualized through nasal endoscopy. In addition, the capabilities of conventional imaging modalities like ultrasound, CT or MRI would no allow the visualization of this submucosal structure and interpretation as a salivary gland. Even if the opening of the gland was noticed on an MRI, there would not be enough information present for scientists to investigate it as a separate major gland, most likely assuming it was part of a larger, known gland.
“As a result of these coinciding factors, the discovery depended on the introduction of molecular imaging with radiolabeled PSMA-ligands,” the researchers explain in their paper, published in Radiotherapy & Oncology. “This provided the required high sensitivity and specificity for detection of salivary gland cells, with a very high contrast-ratio relative to the surrounding PSMA-negative tissues. In combination with 3D anatomical reconstruction of histological information, this allowed us to realize that these cells in fact form distinctive macroscopic gland locations.”
In addition to being a neat surprise discovery, the finding aids Vogel and Valstar’s initial research into the side effects of radiation on patients’ salivary glands. After discovering the tubarial glands, the scientists analyzed data from 723 patients who had undergone radiation treatment. They concluded that the more radiation delivered to the tubarial glands, the more complications patients experienced with eating, swallowing and speaking—just like what happens to the known salivary glands.
"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," said Vogel. "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."
Photo credit: Netherlands Cancer Institute.