Salivary gland stones, or sialoliths, are the most common cause of the obstruction of salivary glands. The mechanism behind the formation of sialoliths has been elusive. Symptomatic sialolithiasis has a prevalence of 0.45% in the general population, is characterized by recurrent painful periprandial swelling of the affected gland, and often results in sialadenitis with the need for surgical intervention. Here, we show by the use of immunohistochemistry, immunofluorescence, computed tomography (CT) scans and reconstructions, special dye techniques, bacterial genotyping, and enzyme activity analyses that neutrophil extracellular traps (NETs) initiate the formation and growth of sialoliths in humans. The deposition of neutrophil granulocyte extracellular DNA around small crystals results in the dense aggregation of the latter, and the subsequent mineralization creates alternating layers of dense mineral, which are predominantly calcium salt deposits and DNA. The further agglomeration and appositional growth of these structures promotes the development of macroscopic sialoliths that finally occlude the efferent ducts of the salivary glands, causing clinical symptoms and salivary gland dysfunction. These findings provide an entirely novel insight into the mechanism of sialolithogenesis, in which an immune system-mediated response essentially participates in the physicochemical process of concrement formation and growth.

Background: Ultrasound is established as a diagnostic tool in salivary glands for obstructive diseases such as sialolithiasis and tumors. Concerning inflammatory diseases and in non-sialolithiasis-caused obstruction, much fewer data are available. In recent years, technical development has allowed a better assessment of the gland parenchyma, and knowledge about intraductal pathologies has increased considerably, which has provided new insights and a new interpretation of ultrasound findings. Objectives: To provide a comprehensive review of the literature that includes our own experiences and to point out the state of the art in ultrasound in the diagnostics of inflammatory and obstructive salivary gland diseases, taking adequate techniques and recent technical developments into consideration. Data sources and study eligibility criteria: A systematic literature search was performed in Pubmed using various specific key words. Results: According to the literature results, including our own experiences, ultrasound is of value in up to >90% of cases presenting with inflammatory and/or obstructive diseases. Technical developments (e.g., elastography) and the application of modified ultrasound techniques (e.g., transoral ultrasound) have contributed to these results. Today, ultrasound is considered a first-line diagnostic tool in these diseases. However, in some inflammatory diseases, the final diagnosis can be made only after inclusion of the anamnesis, clinical symptoms, serologic blood tests, or histopathologic investigation. Conclusions: Ultrasound can be considered as a first-line diagnostic tool in obstructive and inflammatory salivary gland diseases. In obstructive diseases, it may be sufficient for diagnostics in >90% of cases. In inflammatory diseases, ultrasound is at least an excellent screening method and can be used to establish the diagnosis in cases of an early suspicion. In all diseases ultrasound can contribute to better management and can be used for monitoring during follow-up.

Objectives/Hypothesis: To assess long‐term results after the treatment of parotid pleomorphic adenomas (PPAs) using different surgical techniques and focusing on recurrence rates and the risk of adverse effects.Study Design: Retrospective analysis.Methods: Retrospective analysis of 182 patients treated exclusively for PPAs at a tertiary referral center between 2000 and 2004. Thorough follow‐up examinations over a mean period of 13 years were possible in 53.8% (n = 98/182). Tumors were categorized according to the European Salivary Gland Society (ESGS) system to improve the comparison of outcomes. After different surgical resection strategies, recurrence rates, postoperative facial nerve paresis (FNP), and incidence of Frey's syndrome were assessed. The follow‐up period included clinical examinations and imaging of every patient in the treating department.Results: Of 182 patients, extracapsular dissection (ED) was performed in 29.7%, and other surgical modalities (OSMs), including facial nerve dissection, in 70.3%. After the long‐term follow‐up, 98% of all the patients (n = 96/98) were recurrence free. When recurrence rates were compared, no significant differences were noted (P < .331). ED resulted in significantly lower FNP rates compared to OSMs (P < .001). FNP rates significantly increased with size and location of the tumors according to ESGS categories (temporary and permanent FNP, P = .04). Surgical invasiveness corresponded to a significant increase in the incidence of Frey's syndrome (P < .001).Conclusions: ED was associated with the lowest complication rates, but not with a higher risk of recurrence, when compared with OSM in the long‐term course. As ED can be performed in the majority of PPAs, it can be regarded as the treatment of choice whenever possible.Level of Evidence: 4 Laryngoscope, 131:E445–E451, 2021