"Any modern anatomy book will show just three major types of salivary glands: one set near the ears, another below the jaw and another under the tongue. “Now, we think there is a fourth,” said Dr. Matthijs Valstar, a surgeon and researcher at the Netherlands Cancer Institute and an author on the study, published last month in the journal Radiotherapy and Oncology...The new find, Dr. Vogel said, might help explain why people who undergo radiation therapy for cancer of the head or neck so often end up with chronic dry mouth and swallowing problems. Because these obscure glands weren’t known to doctors, “nobody ever tried to spare them” from such treatments, Dr. Vogel said."
The full study is here:
"To our knowledge, this is the first description of paired macroscopic (sero)mucous gland locations in the human posterolateral nasopharyngeal wall, and an indication of their clinical relevance in RT for HNC. Based on its predominant location over the torus tubarius, we propose the name “tubarial glands”. These gland locations were present as macroscopic structures in the PSMA PET/CT scans of all 100 studied individuals, and in two investigated cadavers (one of each gender). Microscopically, they indeed showed salivary gland tissue, highly concentrated bilaterally near the torus tubarius, with macroscopically visible draining duct openings towards the nasopharyngeal wall. High-dose RT to this area lead to significant clinical toxicity. These findings support the identification of the tubarial glands as a new anatomical and functional entity, representing a part of the salivary gland system."