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The aim of this study was to investigate sonographic findings of low-grade malignant tumors of the parotid gland. The sonographic findings of all patients treated for T1-T2 low-grade carcinomas of the parotid gland between 2003 and 2018 were retrospectively examined and compared with those of patients with pleomorphic adenomas for the following parameters: definition of tumor margins, echotexture, echogenicity, shape and vascularization. Statistical analysis was performed using the χ2 test. A p value of

Ultrasound (US) and sialendoscopy (SE) are routinely used in patients presenting with sialolithiasis in the submandibular (SMG) and parotid gland (PG). The objective was to assess the value of the simultaneous application of US and SE in the management of sialolithiasis.Retrospective study.Tertiary referral center for salivary gland diseases.Patients in whom US and SE as single investigation tools were neither conclusive nor useful in the management of sialolithiasis were investigated using both methods simultaneously (simUS + SE).Establishment of the final diagnosis and/or contribution to the planning/performing of treatment in sialolithiasis.74 patients were examined by simUS + SE (58.1 % SMG and 41.9 % PG). In all patients (unclear) hyperechoic reflexes were assessed and/or localized by SE-controlled US navigation. 68.9 % of the patients were investigated for diagnostic or differential-diagnostic reasons including distinguishing extraductal from intraductal calcifications and/or to exclude residual stones after therapy. In 52.7 % simUS + SE was used to plan and/or perform further treatment, in 20.3 % to enable performing a combined approach (all PG) and in 29.7 % to evaluate and plan the most adequate therapy (mainly intraductal vs. extracorporeal shock wave lithotripsy, 68.2 % of these SMG). In two cases SE-controlled and US-guided stone extraction was performed.SimUS + SE is an innovative approach which proved to be very useful in managing sialolithiasis. It added valuable information regarding the establishment of a diagnosis or differential diagnosis, planning and performing the most adequate treatment, intraoperative control of therapy and postoperative follow-up.ZIEL: Ultraschall (US) und Sialendoskopie (SE) werden routinemäßig bei Patienten mit einer Sialolithiasis der Glandula submandibularis (GSM) und Parotis (GP) angewendet. Ziel war es, den Wert der simultanen Anwendung von US und SE (simUS + SE) für die Sicherung der endgültigen Diagnose und/oder ihren Beitrag zur Planung und Durchführung der Therapie der Sialolithiasis zu untersuchen.In einer retrospektiven Studie wurden Patienten, bei welchen US und SE als einzelne Untersuchungsmethoden kein sicheres Ergebnis erbrachten, auf den Mehrwert einer simUS + SE hinsichtlich des weiteren Managements untersucht.Bei 74 Patienten erfolgte eine simUS + SE (58,1 % GSM und 41,9 % GP). Bei allen Patienten wurden (unklare) echoreiche Reflexe mittels Navigation durch US und SE evaluiert und/oder exakt lokalisiert. In 68,9 % der Fälle erfolgte die simUS + SE, um die Diagnose zu sichern bzw. mögliche Differenzialdiagnosen abzuklären. In 52,7 % wurde der simUS + SE benutzt, um die weitere Therapie zu planen und/oder durchzuführen. In 29,7 % aller Fälle half die simUS + SE, die am besten geeignete Therapie (insbesondere intraduktale vs. extrakorporale Schockwellen-Lithotripsie) auszuwählen, in 68,2 % dieser Fälle war die GSM betroffen. In 20,3 % konnte sicherer beurteilt werden, ob eine kombinierte Steinextraktion möglich oder sinnvoll war (alle GP). In 2 Fällen wurde eine US-gesteuerte und SE-kontrollierte Steinextraktion durchgeführt.Die simUS + SE stellt eine innovative Untersuchung dar, welche sich als nützlich für das Management der Sialolithiasis erwiesen hat. Diese war wertvoll für die Sicherung der korrekten Diagnose oder Differenzialdiagnose, Planung und Durchführung der am meisten geeigneten Therapie, darüber hinaus auch bei der intraoperativen Therapiekontrolle und dem postoperativen Follow-up.

Objectives The aim of this study was to investigate the hypothesis of whether extracapsular dissection (ED) of the parotid gland increases the need for revision surgery for benign tumours in comparison to traditional surgical modalities. A further aim of this study was to evaluate and compare the functional outcome of revision procedures after primary ED with other modalities involving the parotid gland in our department. Materials and methods All patients who underwent revision parotid surgery after a primary surgical procedure at a tertiary care hospital (University of Erlangen-Nurnberg) between 2000 and 2016 were included in our study. Data concerning the indication for revision surgery as well as the functional postsurgical outcome were obtained. Results 2465 cases formed our study sample. In total, revision surgery was necessary in 30/2465 cases (1.2%). 1532 patients underwent primary ED, with 17 cases requiring revision (1.1%), whereas 933 cases were managed by means of other facial nerve dissecting surgical modalities, with the indication for revision surgery in 13 cases (1.4%). Our analysis did not reveal a statistically significantly higher need for revision surgery or a higher rate of facial nerve palsies after revision surgery in the group of patients after primary ED. Conclusion The argument in favour of a greater need for revision surgery after primary parenchyma-sparing modalities was not sustained from our data. Due to the low revision rate and the acceptable functional results after revision surgery, we believe that extracapsular dissection is justified in cases where a benign lesion is suspected preoperatively.

OBJECTIVES Parotid duct stenosis may occur with or without accompanying ductal anomalies, with associated differences in their pathogenesis and management. By identifying the characteristics of a stenosis, ultrasound (US) can assist in tailored management of parotid duct stenosis. The objective of this study was therefore to describe the US characteristics of parotid duct stenoses and to evaluate criteria for whether and in what ways these can be distinguished from each other by using US. METHODS A total of 108 patients who presented with parotid duct stenoses (130 parotid glands) were examined with high-resolution US between 2014 and 2017. The stenoses were assessed for duct dilatation, location, signs of ductal anomalies (circular encroachments/webs, duct bending/kinking, and presence of a megaduct) and the echogenicity of the gland parenchyma. RESULTS Ultrasound was able to distinguish between stenoses associated with ductal anomalies and those without anomalies. Webs (82.5% versus 7.8%; P

OBJECTIVE The aim of this study was to investigate and compare the histopathological findings in pleomorphic adenomas (PA) of the parotid and submandibular gland with emphasis on the histological subtype and capsular characteristics. MATERIALS AND METHODS The histopathological specimens of all patients with PAs of the parotid and submandibular gland between 2000 and 2020 were re-examined by an experienced head and neck pathologist. Patients without representative slides allowing evaluation of the whole periphery of the PA were excluded from our study sample. RESULTS Nine hundred and thirty-four patients formed our study sample (327 men, 607 women, male-to-female ratio: 0.53:1). Eight hundred and forty-four cases had a PA in the parotid gland and the remaining 90 in the submandibular gland. Our comparative analysis showed that submandibular PAs are characterized by the consistent presence of an intact anatomical capsule, infrequent occurrence of pseudopodia and satellite nodules, and a low proportion of the high-risk myxoid subtype. CONCLUSION Our study highlights significant differences between PAs of the parotid and submandibular glands in their histopathological characteristics. Their differences likely underlie the favorable surgical outcome observed in PAs of the submandibular glands and may explain the propensity of PAs of the parotid glands for local recurrences.

The aim of this study was to compare several surgical modalities with respect to the incidence of positive margins and focal capsular exposure of pleomorphic adenoma of the parotid gland. The clinical records and histopathological findings of all patients who underwent parotidectomy for pleomorphic adenoma between 2006 and 2020 were retrospectively evaluated (n = 845). The lesion was removed by extracapsular dissection in 577 cases (68%) and facial nerve dissection in 268 (32%). Our analysis did not reveal a statistically significant difference between the examined modalities regarding positive margins (p=0.648) or capsular exposure (p=0.112). Recurrences were detected in 7/845 cases (0.82%) with a mean (range) follow-up time of 82.3 (6-183) months. The choice of surgical method does not seem to have a significant effect on the incidence of positive margins, or on the capsular exposure of a pleomorphic adenoma.

BACKGROUND AND OBJECTIVES To report the first experiences with a newly available Ho:YAG laser system for the treatment of salivary stones. STUDY DESIGN/MATERIALS AND METHODS A retrospective study in a tertiary referral center was conducted. Patients diagnosed with sialolithiasis were treated in Erlangen using the Calculase III™ Ho:YAG laser (Karl Storz, Tuttlingen, Germany). Preset parameters had a frequency of 4 Hz and energy of 0.8-1.2 J, resulting in 3.2-4.8 W. Following total fragmentation, one to two serial sialendoscopies were performed to achieve complete fragment clearance. RESULTS A total of 55 stones in 49 patients were treated; 17 stones in 15 submandibular glands and 38 in 34 parotids. In total, 61 laser lithotripsies (range 1-3 per stone) were performed using various modes (long, short, and burst) and with preset parameters of 4 Hz and energy of 0.8-1.2 J, resulting in effective power of 3.2-4.8 W. Complete fragmentation was achieved in all the accessible stones. Sialendoscopes, fibers, or the mode used had no significant influence on success rates. A multimodal therapy concept was employed to treat stones in 12.24% of the cases; 95.92% of the patients were ultimately stone-free, and all became symptom-free. All glands were preserved. CONCLUSIONS The new Calculase III™ Ho:YAG laser was effective in the treatment of sialolithiasis with no increased risk of complications in the patients or damage to the sialendoscopes. Clinical factors such as the type of gland involved, or the location and size of stones had a greater impact on success rates than the technical or preset parameters. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

The aim of this study was to highlight several misleading imaging and clinical aspects of parotid gland lymphoma, taking our personal experience and relevant literature reports into consideration. The records of all patients diagnosed with lymphoma in the parotid gland between 2005 and 2017 were examined retrospectively. Sixty-seven patients were included in this study. The mean age was 61.4 years. The most frequent histological entities were marginal zone B-cell lymphoma (31.3%) and follicular lymphoma (28.4%). The tumour was stage I in 35 cases (52.2%), stage II in 13 cases (19.4%), stage III in 11 cases (16.4%), and stage IV in eight cases (11.9%). B symptoms were seen in only three patients (4.5%). The diagnosis was made after parotidectomy in 51 cases (76.1%), by core needle biopsy in 14 cases (20.9%), and by means of open biopsy in the remaining two cases (3.0%). Parotid gland lymphoma represents a diagnostically challenging, multifaceted entity that can easily mimic both benign and malignant conditions. This entity should be included in the differential diagnosis of almost all types of parotid lesion, as it seems to play the role of a great pretender.

Objectives To assess results after treatment of difficult/complex sialolithiasis with extracorporeal shock-wave lithotripsy (ESWL) and intraductal pneumatic lithotripsy (IPL). Study design Retrospective study in a tertiary referral center. Methods Altogether, 63 stones were diagnosed in 38 patients with difficult/complex sialolithiasis. Forty-nine stones were treated with fragmentation using both ESWL and IPL. Stones accessible with the sialendoscope were treated primarily with IPL in multiple sialolithiasis. Results Seventy-one ESWL procedures and 57 IPL were performed in our patients. Forty-nine stones were treated by 67 ESWL procedures and 52 IPL. ESWL converted sialoliths from sialendoscopically untreatable into sialendoscopically treatable cases in 94.7%; the treatment then was completed by a total of 52 IPL procedures. ESWL was performed before IPL (81.6%), in combination with IPL (7.9%) and after (10.5%). Complete fragmentation was achieved in 97.9%. Four stones each were treated with ESWL and IPL alone in multiple sialolithiasis. Altogether, 53 stones were treated by 57 IPL procedures. Complete fragmentation was achieved in 98.1% of the 53 stones. ESWL and IPL were the dominant treatment modalities in 84.1% of all 63 stones treated. Of all 38 patients, 92.1% became stone-free and all became symptom-free. All the glands were preserved. Multiple stones were treated in 34.2% of the patients; of these, 92.3% became stone-free. Conclusion These results show that patients with difficult and complex sialolithiasis can be treated with high success rates of > 90% using a multimodal, minimally invasive, and gland-preserving treatment approach. ESWL and IPL played a key role in this multimodal treatment regime in > 80% of stones. Level of evidence 4. Laryngoscope, 128:E332-E338, 2018.

Objectives The aim of this study was to assess the effectiveness of sonography for diagnosing sialolithiasis in comparison with the existing reference standard of direct identification of a stone. Methods A total of 659 glands with signs of obstructive sialadenopathy were evaluated retrospectively. Sonographic examinations of the large head salivary glands had been performed initially in all cases. Direct depiction of a stone during sialoendoscopy or transoral ductal surgery or observation of stone fragmentation with discharge of concrements after extracorporeal shock wave lithotripsy, was regarded as definitive evidence and as the reference standard for the presence of sialolithiasis. The sonographic results were compared with those for direct identification of stones. Results The sensitivity of sonography was 94.7%, with specificity of 97.4%, a positive predictive value of 99.4%, and a negative predictive value of 79.6%. Stones that were not diagnosed correctly on sonography were most often located in the distal area of the duct. Conclusions These results show that sialolithiasis can be diagnosed by sonography with a high degree of certainty. Sonography thus appears to be highly appropriate as the examination method of choice.

Objectives/Hypothesis To assess the long-term results after transoral submandibulotomy for stones located in the deep hilar and intraparenchymal submandibular region. Study Design Retrospective cohort analysis. Methods Retrospective evaluation including all patients treated with transoral submandibulotomy for sialolithiasis at a tertiary referral center. Results Complete stone removal at the first transoral surgical treatment was achieved in 185 of 234 patients (79.1%). One hundred seventy-five of the 234 patients were followed up for a mean of 31.2 ( ± 20.5) months. During the follow-up period, 140 of the 175 patients (80.0%) became symptom free after one operation. In patients with residual symptoms, no further treatment was needed in 12 patients (6.9%) due to the mildness of the symptoms; 23 patients (13.1%) received further therapy, which was successful in 15 cases. Submandibulectomy only had to be performed in 3.4% of the patients with follow-up (6/175). In a questionnaire survey, 91.4% of the patients stated that they would be prepared to have the same operation again. Conclusions These findings show that transoral removal of submandibular sialoliths located in the deep hilum or adjacent intraglandular parenchyma is an effective treatment that can be assisted by additional measures. The techniques described show high success rates, good long-term results, low complication rates, and they avoided the need for submandibulectomy in >95% of cases. Level of Evidence 4. Laryngoscope, 127:2038–2044, 2017

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

Objectives The aim of this study was to assess diagnosis and treatment of submandibular duct stenosis caused by dental prostheses. Study Design This retrospective study included 9 patients with papillary stenosis caused by physical irritation of the Wharton duct ostium by a mandibular dental prosthesis. Diagnostics included physical examination, as well as transcutaneous and transoral ultrasound examinations. Treatment consisted of duct incision, papillotomy, and subsequent sialendoscopy. After surgery, patients were advised to have the dental prosthesis altered by the dentist and to have regular gland massage. Follow-up data were obtained via telephone interviews. The most important outcome parameter was a symptom-free state. Results In all 9 patients, the insertion of the sialendoscope was initially impossible because of the stenosis. After duct incision, sialendoscopy ruled out other obstructive causes and inflammatory states, leaving the dental prosthesis as the only underlying cause of the obstruction. Seven of the 9 treated patients were interviewed after a follow-up period of 28.1 (± 25.4) months. The procedures had resulted in all patients being symptom-free, without any reported complications. Conclusions Mandibular prostheses can cause stenosis of the papillary region with subsequent submandibular duct obstruction. Surgical therapy is easy to perform and results in excellent long-term outcomes.

Transcutaneous ultrasound (TCUS) is an accepted diagnostic method in salivary gland diseases. However, sparse data are available on the use of transoral ultrasound (TOUS) in sialadenopathies. One hundred five patients presenting with various obstructive sialadenopathies were examined using TOUS and TCUS. Ultrasound findings were validated by direct visualization in subsequent sialendoscopy examinations. By TOUS, but not by TCUS, all patients with sialolithiasis (70/105) could be identified and virtually all concrements, even very small ones, were detected and distinguished from artifacts. Ductal stenoses (16/105) could be correctly differentiated from sialoliths, and exceptional insights into the delicate anatomy of parotid duct stenoses were gained. TOUS provided detailed information on other space-occupying lesions (14/105) and circumvented the method-related diagnostic weaknesses of TCUS. As a valuable tool in the diagnosis of obstructive sialadenopathies, TOUS seems superior to TCUS in pathologies involving the distal parotid duct, the submandibular duct system and the floor of the mouth.

• Transoral ultrasound is a simple technique, very helpful for the evaluation of obstructive diseases of the salivary glands. • It overcomes most of the limitations of transcutaneous ultrasound.

To assess long-term results after treatment of parotid pleomorphic adenomas (PPAs) with different surgical techniques, standardized according to the European Salivary Gland Society (ESGS) classification system.We analyzed ESGS categories, occurrence of facial nerve paresis (FNP), Frey's syndrome, histopathology, and recurrences. Surgical modalities were compared, differentiating techniques with and without facial nerve dissection. A strict protocol ensured a postoperative follow-up-period of more than 7 years.205 patients were included. A complete follow-up was possible in 138 patients, 77 of whom underwent extracapsular dissection (ED) and 61 of whom had other surgical modalities (OSMs). ESGS categories correlated with the extent of surgery, significantly with the risk for FNP and Frey's syndrome, but not with recurrences. Recurrences did not differ significantly between ED and OSMs, whereas the risks for FNP (p 0.001 each) and Frey's syndrome (p = 0.000) were significantly higher after OSMs in comparison with ED. Young women with a stroma-rich (myxoid) tumor subtype appear to have the greatest risk for recurrences.ED is the treatment of choice for PPAs, if possible, resulting in similar recurrence rates but significantly fewer comorbidities in comparison with more extensive surgery. After the treatment of PPAs, a long-term follow-up is needed, including imaging.

Objective Persistent, residual, or recurrent stones after transoral duct surgery are always associated with hilar to intraparenchymal and/or multiple sialolithiasis, causing difficulties in the treatment. This study was performed to assess the value of intraductal lithotripsy in the treatment of persistent, residual, or recurrent sialolithiasis after extended duct surgery in the submandibular gland. Study Design Retrospective study covering February 2015 to June 2018. Study Setting Tertiary referral center for salivary gland diseases. Subjects and Methods After extended ductal surgery, 39 patients presenting with persistent, residual, or recurrent stones were treated. Four patients had persistent stones; 16 had residual stones; and 19 presented with recurrent stones. Among these patients, 50 stones were treated with intraductal pneumatic lithotripsy. Fragmentation rate, stone-free rate, and symptom-free rate after treatment with intraductal lithotripsy were outcome measures. Results Of the 39 patients, 97.4% became stone-free, and all were symptom-free. Ninety-eight percent of the stones were completely fragmented. For 23.1% of the patients, >1 stone was treated with intraductal lithotripsy. All patients with persistent stones, 93.7% of those with residual stones, and all with recurrent stones became stone-free and symptom-free. No severe complications developed. Conclusions This study shows that patients presenting with difficult and/or multiple sialolithiasis after extended transoral submandibular duct surgery can be treated with success rates >97%. For multiple sialolithiasis in particular, a multimodal treatment approach with interventional sialendoscopy and intraductal lithotripsy as a central element is a prerequisite for success, as this enables the most difficult part to be performed with high success rates.

The aim of this study was to assess the interrater reliability of ultrasound for diagnosing sialolithiasis. A total of 100 consecutive patients with signs of obstructive sialadenopathy were evaluated. The patients all underwent ultrasound examinations in a standardized manner conducted by one specialist with extensive experience in the management of salivary gland disorders and proficiency in head and neck ultrasonography. The video recordings were sent to six colleagues with comparable experience without providing any further information about the patients' medical history and physical examination. The overall agreement between the seven observers was substantial, with a κ of 0.765 for the 100 cases and a percentage agreement level of 88.29 ± 3.01 % (range: 83-94 %). The range of agreement on this video set for observer pairs varied from substantial to almost perfect agreement (0.663 to 0.878). Among the few false-negative findings (5.4 %), 71.8 % were due to distal sialolithiasis. Two-thirds of the false-positive findings (3.7 %) were due to fibrotic stenosis. The study confirmed the diagnostic value of ultrasound in sialolithiasis and demonstrated a very high level of interrater agreement, even in the absence of additional clinical patient information, thus further underscoring the importance of ultrasound as the examination of first choice in sialolithiasis.ZIEL: Das Ziel dieser Studie war die Beurteilung der Interrater-Reliabilität der Sonografie in der Diagnose der Sialolithiasis. Insgesamt wurden 100 konsekutive Patienten mit Anzeichen einer obstruktiven Sialadenopathie untersucht. Die Patienten unterzogen sich einer standardisierten sonografischen Untersuchung, die von einem HNO- Arzt mit umfangreicher Erfahrung in der Sonographie und in der Behandlung von Speicheldrüsenerkrankungen durchgeführt wurde. Die Videoaufnahmen wurden an 6 Kollegen mit vergleichbarer Erfahrung gesendet, ohne weitere Informationen über die Krankengeschichte und die körperliche Untersuchung der Patienten zu geben. Die Gesamtübereinstimmung zwischen den 7 Beobachtern war substanziell, mit einem κ von 0,765 für die 100 Fälle und einem prozentualen Übereinstimmungsgrad von 88,29 ± 3,01 % (Bereich 83–94 %). Die Bandbreite der Übereinstimmung in diesem Video-Set für Beobachterpaare variierte von substanziell bis nahezu perfekt (0,663 bis 0,878). Unter den wenigen falsch negativen Befunden (5,4 %) waren 71,8 % auf distale Sialolithiasis zurückzuführen. Zwei Drittel der falsch positiven Befunde (3,7 %) waren auf eine fibrotische Stenose zurückzuführen. Die Studie bestätigte den diagnostischen Wert von Ultraschall bei Sialolithiasis und zeigte eine sehr hohe Interrater-Übereinstimmung, auch ohne zusätzliche klinische Patienteninformationen. Dies unterstreicht die Bedeutung von Ultraschall für die Untersuchung der ersten Wahl bei Sialolithiasis.

Objectives/Hypothesis To test the effectiveness of a newly approved pneumatic lithotripter for fragmentation of salivary stones. Study Design Retrospective study in a tertiary referral center. Methods In 44 patients, 49 stones were primarily treated with direct endoscopic guidance using the StoneBreaker. Twenty-three stones were located in the parotid gland and 26 in the submandibular gland. Results Complete fragmentation was achieved combined extracorporeal in 97.7% of the stones. All of the patients became symptom free, and 97.7% were stone free. Three patients underwent lithotripsy procedures. Altogether additional treatment was necessary in five cases to achieve stone clearance. The reason for residual sialolithiasis was intraparenchymal repulsion of a residual fragment (n = 1). The glands were preserved in all cases. Conclusions Endoscopically guided intraductal pneumatic lithotripsy using the StoneBreaker is an effective and promising procedure for the treatment of sialolithiasis. Level of Evidence 4 Laryngoscope, 126:1545–1550, 2016

Background The aim of this study was to evaluate the potential for reducing surgical invasiveness in parotid cystadenolymphomas by means of capsular dissection based on the experience made in our department and on various aspects of these lesions gained from the relevant literature. Methods All patients treated for cystadenolymphomas with extracapsular or capsular dissection at a tertiary referral center between 2000 and 2017 were examined retrospectively. A literature review of various aspects and of different treatment strategies for this lesion was also performed. Results 629 patients were included in the study. 499 had solitary tumors (79.3%) and 130 had unilateral multicentric lesions (20.7%). 595 patients were managed by means of ED, while 34 patients underwent a CD. Our analysis detected an overall occurrence rate of ipsilateral metachronous tumors of 2.06% (13/629), all after extracapsular dissection, with a mean follow-up of 104.1 months. No statistical difference could be found between ED and CD in the overall occurrence rate of ipsilateral metachronous tumors or in the complication rate. No cases of a malignancy arising from a preexisting Warthin tumor could be detected in our study sample. Conclusion A clear potential for reducing surgical invasiveness could be shown. A reliable imaging diagnosis, appropriate patient counseling and high compliance with close follow-up are the basic prerequisites for an acceptable outcome.

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.