Manuscript received 11 March 2026

Revised 19 May 2026

Accepted 21 June 2026

Available online 30 June 2026

J Diagn Treat Oral Maxillofac Pathol 2026; 10: 100319.

DOI: https://doi.org/10.23999/j.dtomp.2026.6.100319     

Under a Creative Commons license (CC BY-NC-SA 4.0)

HOW TO CITE THIS ARTICLE

Cherniak OS, Fesenko II, Demidov VH. Mucous plugs, sialoliths, and foreign bodies of salivary glands: A clinicosonographic review. J Diagn Treat Oral Maxillofac Pathol. 2026;10(6):100319.

 

ABSTRACT

The goal of this narrative review is a comparative analysis of the ultrasound and macroscopic appearance of salivary gland mucous plugs with sialoliths and foreign bodies. The salivary sludge was also considered. In the world there are only two effective methods for diagnosing mucous plugs, ultrasonography and sialendoscopy. The first is simpler, cheaper and easier to perform, but more difficult to interpret for non-experienced clinicians, and the second is more difficult to perform, but easier to visualize and verify on the screen. While numerous cases of sialendoscopic images of mucous plugs in the parotid glands have been documented worldwide, sonographic images of mucous plugs in the Wharton’s duct have been noted by us in only one publication, and publications with sonograms of mucous plugs of the parotid glands, according to our literature search, are completely absent.

KEY WORDS

Ultrasonography, salivary glands, mucous plug, sialolith, foreign body, Wharton’s duct, Stensen’s duct

INTRODUCTION

Obstructive salivary gland disease (OSGD) is characterised by a history of recurrent pain and swelling of the gland [1]. Eating-induced pain (Farhadi et al., 2023) (synonym: salivary colics) and gustatory swelling (Yazbeck et al., 2023) are two most common symptoms of OSGD [2, 3]. OSGD is usually triggered by sialoliths, mucous plugs, foreign bodies, stricture, stenosis or a combination of them [4, 5]. Erkul and Gillespie (2016) describe stricture and stenosis as two types of salivary duct scar [6]. While sialoliths are well-studied both from the point of view of diagnostics [7-9] and management [10, 11], their clinical and sonographic comparison with mucous plugs [12] and foreign bodies [13] is still insufficiently elucidated. Therefore, the main goal of this article is a comparative analysis of the ultrasound and macroscopic appearance of salivary gland mucous plugs with sialoliths and foreign bodies. The salivary sludge was also considered.

MUCOUS PLUGS

Mucus plugs in other parts of the body are also a pathology in demand for research. For example, mucus plugs in the air passages [14]. There is a certain generally accepted difference in the spelling of the name of the plugs in thoracic surgery, pulmonology, and oral and maxillofacial surgery. Mucous plug of a major salivary gland is a soft, “buttery”, light pink/yellowish formation/obstruction in the duct caused by saliva stagnation or increased mucus concentration [15, 16]. Mucous plugs of salivary glands (Fig 1) are also known as mucus plugs, mucosal plugs, mucofibrinous plugs, fibrinous mucus plugs, fibromucinous plugs, or clots of fibrin [12, 17].

 

In 1935 Bruce Pearson described the passage of fibrinous plugs containing large number of eosinophils from the parotid ducts in children [18]. Unfortunately, macroscopic photographs of the plugs were not presented.

 

In 1978 the first report of the use of ultrasonography (USG) for salivary stone detection was published by Pickrell, Trought and Shearin in the Journal of Plastic Surgery [19]. US of a calculus in the parotid gland has been described in their case report paper.

 

The world’s first publication comparing the ultrasound and clinical (macroscopic) appearance of mucous plugs with salivary stone was published in May 2019 (treated in August 2014) [12]. Thus, 41 years have passed from the description of the USG picture of a sialolith to the description of the USG picture of a salivary gland mucous plug. Submandibular mucous plugs in the case of 2019 were sonographically detected and removed from the Wharton’s duct simultaneously with sialolith at the stages of treatment of exacerbation of salivary stone disease [12]. Clinically, submandibular mucous plug and sialolith (i.e., salivary stone) can be compared to “butter” and “stone” in terms of consistency to the touch [12].

 

Endoscopy historically emerged later than USG, so its use, in particular for the major salivary glands, only began in the early 1990s (Nahlieli, 2004) [20]. In 1991, Konigsberger et al., highlighted endoscopic controlled laser lithotripsy in the treatment of sialolithiasis [21]. In 1990, 1991, and 1993, Katz described endoscopy of the major salivary glands and demonstrated how it is possible to extract sialoliths via the natural passages using a miniaturized basket catheter, avoiding the need for more extensive surgery [22-24].

 

In 1997 (Nahlieli et al.), there were no mentions of endoscopic images of mucous plugs, but mainly images of sialoliths and statistical data on endoscopic results [25].

 

Marchal et al. (1999) upon their description of interventional sialendoscopy also demonstrate endoscopic images exclusively of sialoliths [26].

 

In 2002, Marchal et al., in their report of submandibular diagnostic and interventional sialendoscopy, demonstrate approaches to endoscopic removal of culculi [27]. We confirm the Marchal’s data (2005), sialendoscopy is incredibly excellent for visualizing the ductal system of the salivary glands with their ramifications [28]. We were unable to determine exactly in which year the endoscopic image of mucous plugs of salivary was first published. The earliest such image was found in the book chapter by Marchal in 2007 [29]: “Floating mucous plugs can be seen alone or in conjunction with salivary stones or stenotic processes. It has been suggested that these “mucous plugs” present in the ductal system may represent the nidus for the development of calculi”. That is, 17 years have passed since the application of endoscopy for the management of sialolithiasis. Yu et al. (2008) presented sialendoscopy images of parotid mucous plug upon treatment of chronic obstructive parotitis [30].

 

As of 2026, the appearance of mucous plugs through sialendoscopy has been described in a much larger number of studies. In 2021, Fusconi et al. devoted the highly important article to interpretation of the mucous plugs through sialendoscopy [16]. In their study, the mucous plugs were pale pink. The chronology of the introduction of sialendoscopy is detailed in Fritsch’s work (2009) [31].

 

Chikamatsu et al. (2006) presented two sialodochitis fibrinosa patients with recurring bilateral parotid swelling [32]. In both patients, secretion of mucous plugs containing numerous eosinophils was observed from Stensen’s ducts. The article’s black and white photo shows a 2-cm mucous plug extruded from the main parotid duct. Our literature search did not yield data on the ultrasound appearance of mucous plugs of the parotid or sublingual glands. Thus, the 2019 publication, at the time of writing, was the first clinical and ultrasound presentation of mucous plugs of the main duct of the submandibular gland [12].

 

Karwowska and Turner (2021) [5] state the following: “The submandibular glands have a higher concentration of mucous cells than the parotid glands, and are thus more likely to form obstructive mucous plugs. When a mucous plug is the sole cause of obstruction, it is referred to as a primary mucous obstruction. If a mucous plug occurs in conjunction with another obstructive process, such as a sialolith or a stricture, it is referred to as a secondary mucous obstruction.” Although some authors believe that the formation of mucous plugs is more likely in the submandibular glands, other sources indicate a higher probability of detecting plugs in the parotid glands. According to Sánchez Barrueco, Díaz Tapia, et al. (2025) in 84% of cases, mucous plugs occur in the parotid glands [4]. In 16% of cases, mucous plugs occur in the submandibular glands [4].

 

Floating mucous plugs can be seen alone or in conjunction with sialoliths or stenotic processes (Marchal, 2007) [27]. It has been suggested that these “mucous plugs” present in the ductal system may represent the nidus for the development of calculi (Marchal, 2007) [27]. The author demonstrate unique sialoendoscopic images, namely: (1) Mucous plug attached to the calculus which impairs intraductal vision, (2) mucosal plug which is mechanically detached by gently tapping on the calculus with the laser fiber tip, and (3) extraction of this plug using a wire basket [27].

 

According to sialoendoscopy, with swelling of the submandibular glands, mucous plugs are found in 3% of cases, stones in 91% of cases, and stenosis in 6% of cases (Chuangqi Yu et al., 2013) [33]. With swelling of the parotid glands, completely different data are noted: mucous plugs are found in 14% of cases, sialoliths in 11% of cases, and stenosis in 75% of cases.

 

Gür et al. in 2023 highlighted yellowish fibromucinous plugs of the parotid glands upon Kussmaul disease (also known as sialodochitis fibrinosa) [34, 35]. Tymofieiev (2025) describes the saliva obtained with such parotid sialadenitis as stagnant and viscous saliva with strands (flakes) of fibrin [36].

 

Baer et al. (2017) in their study about eosinophilic sialodochitis highlighted redefinition of “allergic parotitis” and “sialodochitis fibrinosa” [17]. The authors did a good review of the literature on mucous plugs in this type of parotitis [17]. Here is their data: “The mucus plugs measured up to 3 cm in length (Pearson, 1935; Yoshioka et al., 1997) [18, 37] with variable consistency: sometimes gelatinous (Pollak et al., 2009; Shimada et al., 2006; Tsuchiya et al., 2012) [38-40], but sometimes firm enough to form casts of the ducts (Motosugi et al., 1998) [41]”.

 

Hayashi et al. (2016) presented gelatinous plug (clots of fibrin) discharged from parotid papilla [42]. Pressure on parotid glands bilaterally induced discharge of gelatinous plugs from parotid papillae. No discharge of pus and no calcifications were observed.

 

Salazar and Celestin (2020) reported about microscopic features of mucofibrinous plugs of the submandibular glands upon Kussmaul disease [43].

 

Baer et al. (2017) presented unique mucus plug cytology data [17]. Mucus plug expressed from Wharton’s duct with gland massage showed numerous eosinophils. Chuangqi et al. (2013) described how 4 polyps and 7 mucus plug cases were treated successfully by forceps and continuous rinsing under sialoendoscopy [33].

 

The shape of the mucous plugs on sialoendoscopic images of the parotid gland ducts (Jung et al., 2025) was elongated, unlike mucous plugs of the submandibular gland duct (Cherniak and Fesenko, 2019) study [44, 12]. Mucous plugs of the submandibular glands have isoechoic heterogeneous ultrasound appearance and no acoustic shadowing [12].

 

Pang et al. (2023) described a rare case of sialendoscopic removal of metastatic adenocarcinoma in a mucous plug from Stensen’s duct [45].

 

According to Steck et al. (2016), most of endoscopies (85%) were performed under general anesthesia in an outpatient fashion, but the procedure can be performed under local anesthesia too [46].

 

It is interesting that surgeon-performed ultrasound for chronic obstructive sialadenitis helps predict sialendoscopic findings and outcomes (Larson et al., 2017) [6].

 

The identified mucous plugs only in the ducts of the parotid and submandibular glands emphasize that the anatomy of these ducts and the physiology of these glands are favorable for the formation of these intraductal formations.

SIALOLITHS

While the presence of mucous plugs has been reliably established endoscopically, by USG, macro- and microscopically in the parotid and submandibular glands and their ducts, sialoliths have been detected in all major salivary glands [8, 47-50] as well as in the minor ones [51-53].

 

Zenk et al. (2012) and Sánchez Barrueco, López-Acevedo Cornejo, et al. (2025) detailed theories about formation of sialoliths [54, 15]. Three possible substrates for the formation of the initial core [15]: (1) floating mucoid materials in the Wharton duct (generically referred to as a mucus plug) [12], (2) vesicles filled with organic matter or lipid droplets [55] that give rise to so-called sialomicroliths, and (3) a foreign body that penetrates retrogradely from the oral cavity [13].

 

In 75.68% of cases, sialoliths occur in the submandibular glands and its ducts (Figs 2 and 3) (Sánchez Barrueco, Díaz Tapia, et al., 2025) [4]. In 24.32% of cases, sialoliths occur in the parotid glands and its ducts (Figs 4 and 5) [4]. The incidence of sublingual sialoliths has been reported as 0 to 6.4% (Hong and Yang, 2003) [58]. Interestingly, numerous sialoliths can be found in the sublingual gland, which resemble phleboliths in shape, namely pearl-shaped [59, 60].

 

Endoscopic classification of salivary lithiasis is perfectly described by Marchal et al. (2008) [61]. An interesting element of this classification is the division into floating and fixed [61]. It has already been proven that sialolith flotation can be verified using USG (Tymofieiev and Cherniak, 2019) [62].

 

Lustmann et al. (1990) found swelling to be present in 94% of their 245 cases of sialolithiasis, with pain occurring in 65.2%, the presence of purulence in 15.5%, and complete lack of symptoms in 2.4% of their cases [63, 64].

 

Our team, considering such diagnostic options as sialendoscopy, sialography, radiography, computed tomography and USG, considers the latter method to be the easiest, simplest and safest way to verify salivary calculi. How reliable is USG in the assessment of sialolithiasis is described in the article by Terraz et al. (2013) [65]. A proposal for standardized USG analysis of the salivary glands is described in detail by Hoffman et al. (2024) [66]. Typically, sialoliths are visualized as hyperechoic curved lines with posterior acoustic shadowing.

 

Howlett et al. (2004) have provided an excellent sonographic description and images of the submandibular gland and its appearance in sialolithiasis [67].

 

Bimanual palpation (i.e., two-handed palpitation) during USG (digital palpation of the floor of mouth with one hand while externally applying the probe with the other hand) can facilitate visualization of ductal stones (Orloff et al., 2009) [68]. The bilateral glands should always be examined for comparison and identification of individual differences, unilateral diseases, and systemic processes [68].

 

With USG, the difficulty of establishing the exact localization of a sialolith, mucous plug, or foreign body is higher in areas of the accessory parotid gland and due to the significant arborization in parotid gland itself (Amiel et al., 2024) [57]. The computed tomography sialography is recommended in such cases [57]. Despite intra- and periparenchymal calculi are rare (Bodner, 1999) [48] we present a 57-year-old male with a sialolith located between the capsule and the gland parenchyma (Fig 5B). Oliveira et al. (2014) highloghted a bedside emergency ultrasound in a case of acute parotid duct sialolithiasis [9]. Numerous studies have analyzed the use of ultrasound in sialolithiasis, and each of them is worth considering [69-78].

 

Hosokawa et al. (2023) emphasized that USG is often the first modality of choice for pediatric patients with OSGD due to the absence of radiation exposure and sedation during radiological examination [73]. Compared with adult calculi, paediatric calculi tend to be located on the distal side of the duct (i.e., closer to the sublingual papilla) (Hosokawa et al., 2023; Chung et al., 2007) [73, 79].

 

Kim et al. (2013) summarized the clinical data of young children with parotid sialolithiasis [80]. Cases of patients aged 2 to 5 years were analyzed [80]. In all cases, sialoliths were in the Stensen’s duct [80].

 

Speaking about radiological examinations, it is worth noting that classic laminated appearance is the characteristic appearance of salivary stones on radiographs, as confirmed in Figure 2A (Benson, 2014) [81].

 

Kraaij et al. (2014) described salivary microlith (i.e., sialomicrolith) [82] and Mostafavi Tabatabaee et al. (2019) provided a literature review of giant salivary sialoliths larger than 30 mm (i.e., salivary megaliths) [83]. When detecting rounded calcifications in the salivary gland area, it is important to conduct differential diagnosis with arteriovenous malformations [84]. The submandibular gland was previously named as submaxillary gland. Therefore, inflammation of this gland (i.e., sialadenitis) was called submaxillitis. Some surgeons continue to use this term today. Teymoortash et al. (2003) proved through serial histological examination of the entire Wharton’s duct in four samples revealed no anatomical correlation for the presence of a sphincter [85].

 

Kopeć et al. (2013) presented an algorithm of salivary gland obstructive pathology treatment, according to Koch et al. (2009) [11, 10]. The classic surgical approach for submandibular gland removal is open, transcervical approach (Beahm et al., 2009) [86]. Submandibular gland surgery using this approach is described in an excellent step-by-step manner with images in the publication by Tymofieiev (2007) [87].

 

Savchuk and Fesenko in 2021 demonstrated a transcutaneous removal of sialolith with a flow of pus in a patient with phlegmon of the flour of mouth and lateral neck due to the exacerbation of the chronic calculous submaxillitis [88].

 

There are important publications about sialolithiasis in an accessory submandibular gland and residual Wharton’s duct after excision of a submandibular gland [89, 90]. Therefore, it is worth understanding this anatomical feature of the gland.

FOREIGN BODIES

Fish bone, fingernail, vegetal nidus, thorn, piece of hair, metal body, and other particles are among numerous foreign bodies penetrated the major salivary glands [13]. Savchuk and Nozhenko (2020) performed and interesting report of a foreign body retrograde migration to the intraglandular duct of the submandibular gland with a developing of foreign body-induced sialolithiasis [13]. Additionally, an analysis of USG, surgery, and literature published during the last 124 years was conducted.

 

Foreign bodies can enter the parotid gland both intraoral through the Stensen’s duct and extraoral through penetration of a foreign body through a wound on the skin Ahmed et al. (2015) [91].

 

Gill et al. (2016) described in their study an ultrasound appearance of foreign body (fish bone) in the parotid gland [92]. Paper included gray scale sonogram and cine loops.

 

In 2025, Zheng et al. published a case with Stensen’s duct penetration and sialolith formation as a rare complication of thread lifting surgery [93]. Sialendoscopy revealed calculus deposited on a “thread-like foreign body”.

 

Luo et al. (2022) illustrated transcutaneous and transoral USG precisely located the splinter within Wharton’s duct [94]. Shortly thereafter, the bamboo splinter was spontaneously discharged while eating, which allowed complete remission of pain and swelling. 

 

Oz et al. (2022) presented an ultrasound image of a foreign body with vegetative morphology, which settles into the parotid gland by retrograde migration [95].

 

Also, numerous fish bone-induced sialoliths are dscribed in details [13, 96, 97].

 

Interestingly, Smith and Jones (2024) demonstrated the possibility of the foreign body ultrasound verification in dogs in the article “Ultrasound diagnosis and sialadenectomy confirming a mandibular salivary gland vegetative foreign body and chronic sialadenitis in a dog” [98].

 

Removal of a foreign body depends on localization [13], in principle, almost the same as removal of a stone.

SLUDGE

Salivary sludge is thick saliva with high protein content that can block salivary duct [99]. Ductal sludge (i.e., salivary sludge) sonographic visualization is featured in a book chapter by Bradley (2000) [100]. According to Hoffman and Iowa Head and Neck Protocols (2017), the dynamic movement of sludge is primarily observed via dynamic real-time ultrasound imaging (sonopalpation) [69].

 

The term “sludge” is also used in general medicine, for example “biliary sludge” (Lee et al., 2018) [102]. Sludge is a collection of the precipitants of bile that collects in layers within the gallbladder and appears sonographically as mildly echogenic material without acoustic shadowing [101].

CONCLUSION

In the world there are only two effective methods for diagnosing mucous plugs, ultrasonography and sialendoscopy. The first is simpler, cheaper and easier to perform, but more difficult to interpret for non-experienced clinicians, and the second is more difficult to perform, but easier to visualize and verify on the screen.

 

Summing up the comparison of such pathological objects of the salivary glands as mucous plugs, sialoliths, foreign bodies and salivary sludge, it is worth noting the extremely high diagnostic capabilities of USG.

 

Table 1 demonstrates the sonographic and clinical comparison of pathological objects of the salivary glands [102].

DISCLOSURES

Author Contributions: Concept and Design – I.I.F.; Literature Search – O.S.C.; Writing – I.I.F., O.S.C.; Critical Review – V.H.D.

Declaration of Interests: The authors have no conflicts of interest to declare.

Informed Consent: Written consent was obtained from patients for publication of photographs.

Fundings: No funding was received for this study.

Peer-Review: Externally peer-reviewed.

AI Statement: The authors declared that artificial intelligence was not used in this article.

REFERENCES (102)

1. Atienza G, López-Cedrún JL. Management of obstructive salivary disorders by sialendoscopy: a systematic review. Br J Oral Maxillofac Surg. 2015;53(6):507-519. https://doi.org/10.1016/j.bjoms.2015.02.024

2. Farhadi M, Mohebbi S, Daneshi A, et al. The therapeutic outcome of sialendoscopy in patients with sialoadenitis. Iran J Otorhinolaryngol. 2023;35(127):91-96. https://doi.org/10.22038/ijorl.2023.63433.3174

3. Yazbeck A, Iwanaga J, Walocha JA, et al. The clinical anatomy of the accessory submandibular gland: a comprehensive review. Anat Cell Biol. 2023;56(1):9-15. https://doi.org/10.5115/acb.22.118

4. Sánchez Barrueco A, Díaz Tapia G, Alcalá Rueda I, et al. Quantifying the impact of chronic obstructive sialadenitis on quality of life. J Clin Med. 2025;14(21):7560. https://doi.org/10.3390/jcm14217560

5. Karwowska NN, Turner MD. Etiology, diagnosis, and surgical management of obstructive salivary gland disease. Front Oral Maxillofac Med. 2021;3:17. https://doi.org/10.21037/fomm-20-73

6. Larson AR, Aubin-Pouliot A, Delanges E, et al. Surgeon-performed ultrasound for chronic obstructive sialadenitis helps predict sialendoscopic findings and outcomes. Otolaryngol Head Neck Surg. 2017;157(6):973-980. https://doi.org/10.1177/0194599817728867

7. Gonçalves M, Schapher M, Iro H, et al. Value of sonography in the diagnosis of sialolithiasis: comparison with the reference standard of direct stone identification. J Ultrasound Med. 2017;36(11):2227-2235. https://doi.org/10.1002/jum.14255

8. Demidov VH, Khrulenko SI. Sialoliths of submandibular gland and Wharton’s duct: orthopantomography. J Diagn Treat Oral Maxillofac Pathol. 2021;5(7):77-86. https://doi.org/10.23999/j.dtomp.2021.7.1

9. Oliveira LG, Hurst ND, Magajna PW. Bedside emergency ultrasound in a case of acute parotid duct sialolithiasis. J Emerg Med. 2014;47(2):e49-e51. doi:10.1016/j.jemermed.2014.04.022

10. Koch M, Zenk J, Iro H. Algorithms for treatment of salivary gland obstruction. Otolaryngol Clin N Am. 2009;42(6):1173-1192. https://doi.org/10.1016/j.otc.2009.08.002

11. Kopeć T, Wierzbicka M, Szyfter W, Leszczyńska M. Algorithm changes in treatment of submandibular gland sialolithiasis. Eur Arch Otorhinolaryngol. 2013;270(7):2089-2093. https://doi.org/10.1007/s00405-013-2463-7

12. Cherniak OS, Fesenko II. Effectiveness of ultrasound in verification of the mucus plugs and sialoliths of the Wharton`s duct. J Diagn Treat Oral Maxillofac Pathol. 2019;3(5):144-153. https://doi.org/10.23999/j.dtomp.2019.5.3

13. Savchuk LA, Nozhenko OA. Foreign body retrograde migration to the intraglandular duct of the submandibular gland with a developing of foreign body-induced sialolithiasis: analysis of ultrasonography, surgery, and literature published during last 124 years. J Diagn Treat Oral Maxillofac Pathol. 2020;4(3):53-59. https://doi.org/10.23999/j.dtomp.2020.3.2

14. Panchabhai TS, Mukhopadhyay S, Sehgal S, et al. Plugs of the air passages: A clinicopathologic review. Chest. 2016;150(5):1141-1157. https://doi.org/10.1016/j.chest.2016.07.003

15. Sánchez Barrueco Á, López-Acevedo Cornejo MV, Aragonés Sanzen-Baker W, et al. Evolutionary conformation model of salivary gland lithiasis. Front Oral Health. 2025;6:1610977. https://doi.org/10.3389/froh.2025.1610977

16. Fusconi M, Meliante PG, Pagliuca G, et al. Interpretation of the mucous plug through sialendoscopy. Oral Dis. 2022;28(2):384-389. https://doi.org/10.1111/odi.13796

17. Baer AN, Okuhama A, Eisele DW, et al. Eosinophilic sialodochitis: redefinition of 'allergic parotitis' and 'sialodochitis fibrinosa'. Oral Dis. 2017;23(7):840-848. https://doi.org/10.1111/odi.12595

18. Bruce Pearson RS. Recurrent swelling of the parotid glands. Arch Dis Child. 1935;10(59):363-376. https://doi.org/10.1136/adc.10.59.363

19. Pickrell KL, Trought WS, Shearin JC. The use of ultrasound to localize calculi within the parotid gland. Ann Plast Surg. 1978;1(6):542-546. https://doi.org/10.1097/00000637-197811000-00003

20. Nahlieli O. Salivary gland inflammatory disorders in children. In: Kaban LB, Troulis MJ, eds. Pediatric Oral and Maxillofacial Surgery. Elsevier Science; 2004:ch 13. https://doi.org/10.1016/B978-0-7216-9691-1.50018-1

21. Königsberger R, Feyh J, Goetz A, et al. Die endoskopisch kontrollierte Laserlithotripsie zur Behandlung der Sialolithiasis [Endoscopic controlled laser lithotripsy in the treatment of sialolithiasis]. Laryngorhinootologie. 1990;69(6):322-323. https://doi.org/10.1055/s-2007-998200

22. Katz P. Un nouveau mode d'exploration des glandes salivaires: la fibroscopie [New method of examination of the salivary glands: the fiberscope]. Inf Dent. 1990;72(10):785-786.

23. Katz P. Endoscopie des glandes salivaires [Endoscopy of the salivary glands]. Ann Radiol (Paris). 1991;34(1-2):110-113.

24. Katz P. Nouvelle thérapeutique des lithiases salivaires [New treatment method for salivary lithiasis]. Rev Laryngol Otol Rhinol (Bord). 1993;114(5):379-382.

25. Nahlieli O, Baruchin AM. Sialoendoscopy: three years' experience as a diagnostic and treatment modality. J Oral Maxillofac Surg. 1997;55(9):912-920. https://doi.org/10.1016/s0278-2391(97)90056-2

26. Marchal F, Dulguerov P, Lehmann W. Interventional sialendoscopy. N Engl J Med. 1999;341(16):1242-1243. https://doi.org/10.1056/NEJM199910143411620

27. Marchal F, Barki G, Dulguerov P, et al. Submandibular diagnostic and interventional sialendoscopy: new procedure for ductal disorders. Ann Otol Rhinol Laryngol. 2002;111(1):27-35. https://doi.org/10.1177/000348940211100105

28. Marchal F. Endoscopie des canaux salivaires: toujours plus petit, toujours plus loin? [Salivary gland endoscopy: new limits?]. Rev Stomatol Chir Maxillofac. 2005;106(4):244-249. https://doi.org/10.1016/s0035-1768(05)85853-x

29. Marchal F. Sialendoscopy. In: Myers EN, Ferris RL, eds. Salivary Gland Disorders. Springer; 2007:ch 6.

30. Yu C, Zheng L, Yang C, Shen N. Causes of chronic obstructive parotitis and management by sialoendoscopy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;105(3):365-371. https://doi.org/10.1016/j.tripleo.2007.08.008

31. Fritsch MH. Sialendoscopy and lithotripsy: literature review. Otolaryngol Clin North Am. 2009;42(6):915-926. https://doi.org/10.1016/j.otc.2009.09.001

32. Chikamatsu K, Shino M, Fukuda Y, et al. Recurring bilateral parotid gland swelling: two cases of sialodochitis fibrinosa. J Laryngol Otol. 2006;120(4):330-333. https://doi.org/10.1017/S0022215106000296

33. Chuangqi Y, Chi Y, Lingyan Z. Sialendoscopic findings in patients with obstructive sialadenitis: long-term experience. Br J Oral Maxillofac Surg. 2013;51(4):337-341. https://doi.org/10.1016/j.bjoms.2012.07.013

34. Gür H, Özcan C, Güven O, et al. Diagnostic and therapeutic value of sialendoscopy in a patient with Kussmaul disease: A case report. B-ENT. 2023;19(3):184-187. https://doi.org/10.5152/B-ENT.2023.221087

35. Kussmaul I. Anfallweise auftertende Speichelgeschwulst [Salivary tumors that appear in fits and starts]. Berlin Klin Wschr. 1879;15.

36. Tymofieiev OO. Non-neoplastic diseases of the salivary glands. In: Tymofieiev OO, ed. Surgical Dentistry and Maxillofacial Surgery. Vol 2. Marchenko TV; 2025:chap 2. Ukrainian.

37. Yoshioka Y, Makino K, Sakoda K, et al. Sialodochitis fibrinosa of the parotid glands: A case report. Kōkū Intōka (Stomato-pharyngology).1997;9:409-416.

38. Pollak N, Templer JW, Esebua M, et al. Episodic painful parotid swelling caused by sialodochitis with eosinophilic inflammation: a new entity. Otolaryngol Head Neck Surg. 2009;140(1):132-133.

39. Shimada T, Okano H, Hisa Y. A case of severe dilatation of the parotid duct due to fibrinous sialodochitis. Acta Otolaryngol. 2006;126(10):1112-1114.

40. Tsuchiya A, Aizawa N, Sato K, Takahashi S. Three cases of sialodochitis fibrinosa. Kōkū Intōka (Stomato-pharyngology). 2012;25(2):173-177.

41. Motosugi H, Itoh H, Tachibana M, et al. Two cases of sialodochitis fibrinosa. Kōkū Intōka (Stomato-pharyngology). 1998;10(3):345-349.

42. Hayashi K, Onda T, Ohata H, et al. Case of suspected sialodochitis fibrinosa (Kussmaul's disease). Bull Tokyo Dent Coll. 2016;57(2):91-96. https://doi.org/10.2209/tdcpublication.2015-0028

43. Salazar P, Celestin J. M104 Sialodochitis fibrinosa: an uncommon and possibly allergic disease of the salivary glands. Ann Allergy Asthma Immunol. 2020;125(5 Suppl):S67. https://doi.org/10.1016/j.anai.2020.08.219

44. Jung HS, Chang IS, Kim JY, et al. Role of ultrasonography in the diagnosis and management of chronic recurrent sialadenitis with sialendoscopy. J Korean Assoc Oral Maxillofac Surg. 2025;51(2):117-123. https://doi.org/10.5125/jkaoms.2025.51.2.117

45. Pang SL, Lo AWI, Wang R, Su YX. Sialendoscopic removal of metastatic adenocarcinoma in a mucous plug from Stensen’s duct. Int J Oral Maxillofac Surg. 2023;52(10):1025-1027. https://doi.org/10.1016/j.ijom.2023.01.011

46. Steck JH, Stabenow E, Volpi EM, Vasconcelos EC. The learning progression of diagnostic sialendoscopy. Braz J Otorhinolaryngol. 2016;82(2):170-176. doi:10.1016/j.bjorl.2015.10.007

47. Demidov VH, Ripolovska OV. How multiple the submandubular gland sialoliths can be? J Diagn Treat Oral Maxillofac Pathol. 2019;3(7):174-175. https://doi.org/10.23999/j.dtomp.2019.7.2

48. Bodner L. Parotid sialolithiasis. J Laryngol Otol. 1999;113(3):266-267. https://doi.org/10.1017/s0022215100143750

49. Nikulin DS, Fesenko II, Cherniak OS. Sialoliths in ipsilateral Bartholin`s and Wharton`s duct: the first clinical and ultrasound report. J Diagn Treat Oral Maxillofac Pathol 2020;4(7):112–8. https://doi.org/10.23999/j.dtomp.2020.7.2

50. Liao LJ, Hsiao JK, Hsu WC, Wang CP. Sublingual gland sialolithiasis: a case report. Kaohsiung J Med Sci. 2007;23(11):590-593. https://doi.org/10.1111/j.2410-8650.2007.tb00003.x

51. Huang HK, Hwang MJ, Chiang CP, Jin YT. Sialoliths in the minor salivary glands of the upper lip. J Dent Sci. 2023;18(3):1392-1394. https://doi.org/10.1016/j.jds.2023.01.032

52. Tanna N, Koshal S. Rare sialoliths of the minor salivary glands: a case series and review of the literature. Oral Surgery. 2016;9(2):107-112. https://doi.org/10.1111/ors.12164

53. Ben Lagha N, Alantar A, Samson J, Chapireau D, Maman L. Lithiasis of minor salivary glands: current data. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;100(3):345-348. https://doi.org/10.1016/j.tripleo.2004.12.023

54. Zenk J, Koch M, Klintworth N, et al. Sialendoscopy in the diagnosis and treatment of sialolithiasis: a study on more than 1000 patients. Otolaryngol Head Neck Surg. 2012;147(5):858-863. https://doi.org/10.1177/0194599812452837

55. Tanaka N, Ichinose S, Adachi Y, et al. Ultrastructural analysis of salivary calculus in combination with x-ray microanalysis. Med Electron Microsc. 2003;36(2):120-126. https://doi.org/10.1007/s00795-002-0210-z

56. Iwanaga J, Tubbs RS, Kitagawa N, et al. Facial landmark-based localization of the parotid duct: a cadaveric study with ultrasonographic feasibility assessment. Sci Rep. 2026;16(1):11082. https://doi.org/10.1038/s41598-026-41701-1

57. Amiel T, Shauly O, Istoyler EG, et al. The anatomical pattern of ductal arborization in parotid glands using cone-beam computerized sialography. Clin Anat. 2024;37(8):878-885. https://doi.org/10.1002/ca.24136

58. Hong KH, Yang YS. Sialolithiasis in the sublingual gland. J Laryngol Otol. 2003;117(11):900-902. https://doi.org/10.1258/002221503322542959

59. Choi J, Kim IK, Oh NS. Multiple sialoliths in sublingual gland: report of a case. Int J Oral Maxillofac Surg. 2002;31(5):562-563. https://doi.org/10.1054/ijom.2002.0253

60. Lee JH, No YH, Cha YW, Kim SW. A case of multiple sialoliths in sublingual gland misdiagnosed as sialoliths in submandibular gland. Korean J Otolaryngol-Head Neck Surg. 2011;54(1):81-84. https://doi.org/10.3342/kjorl.2011.54.1.81

61. Marchal F, Chossegros C, Faure F, et al. Lithiases et sténoses salivaires. Une classification pratique des pathologies non tumorales [Salivary stones and stenosis. A comprehensive classification]. Rev Stomatol Chir Maxillofac. 2009;110(1):e1-e4. https://doi.org/10.1016/j.stomax.2008.10.002

62. Tymofieiev OO, Cherniak OS. Ultrasound in the detection of floating sialoliths. J Diagn Treat Oral Maxillofac Pathol. 2019;3(8):196-197. https://doi.org/10.23999/j.dtomp.2019.8.2

63. Lustmann J, Regev E, Melamed Y. Sialolithiasis. A survey on 245 patients and a review of the literature. Int J Oral Maxillofac Surg. 1990;19(3):135-138. https://doi.org/10.1016/s0901-5027(05)80127-4

64. Carlson ER. Diagnosis and management of salivary gland infections. Oral Maxillofac Surg Clin North Am. 2009;21(3):293-312. https://doi.org/10.1016/j.coms.2009.04.004

65. Terraz S, Poletti PA, Dulguerov P, et al. How reliable is sonography in the assessment of sialolithiasis?. AJR Am J Roentgenol. 2013;201(1):W104-W109. https://doi.org/10.2214/AJR.12.9383

66. Hoffman HT, Koch M, Witt RL, et al. Proposal for standardized ultrasound analysis of the salivary glands: Part 1 submandibular gland. Laryngoscope Investig Otolaryngol. 2024;9(1):e1224. https://doi.org/10.1002/lio2.1224

67. Howlett DC, Alyas F, Wong KT, et al. Sonographic assessment of the submandibular space. Clin Radiol. 2004;59(12):1070-1078. https://doi.org/10.1016/j.crad.2004.06.025

68. Orloff LA, Hwang HS, Jecker P. The role of ultrasound in the diagnosis and management of salivary disease. Oper Tech Otolaryngol Head Neck Surg. 2009;20(2):129-135. https://doi.org/10.1016/j.otot.2009.02.004

69. Hoffman H, ed. Salivary ultrasound sonopalpation for stone favorable for transoral removal. Iowa Head and Neck Protocols. October 30, 2017. Accessed January 05, 2026. https://iowaprotocols.medicine.uiowa.edu/protocols/salivary-ultrasound-sonopalpation-stone-favorable-transoral-removal

70. Schapher M, Goncalves M, Mantsopoulos K, Iro H, Koch M. Transoral ultrasound in the diagnosis of obstructive salivary gland pathologies. Ultrasound Med Biol. 2019;45(9):2338-2348. https://doi.org/10.1016/j.ultrasmedbio.2019.05.019

71. Koch M, Schapher M, Goncalves M, Iro H, Mantsopoulos K. Simultaneous application of ultrasound and sialendoscopy: experience in the management of stenosis and other non-sialolithiasis-related salivary gland disorders. Eur Rev Med Pharmacol Sci. 2020;24(5):2196-2204. https://doi.org/10.26355/eurrev_202003_20485

72. Lystad H, Yu E, Subramony R. Parotid sialolithiasis diagnosed on point of care ultrasound (POCUS). POCUS J. 2025;10(1):104-106. https://doi.org/10.24908/pocusj.v10i01.18657

73. Hosokawa T, Tanami Y, Sato Y, et al. Clinical audit of ultrasonography for detecting sialoliths in the submandibular gland in paediatric patients: A comparison to computed tomography and magnetic resonance imaging. Australas J Ultrasound Med. 2023;27(1):19-25. https://doi.org/10.1002/ajum.12370

74. Hoffmann B. Sonographic bedside detection of sialolithiasis with submandibular gland obstruction. Am J Emerg Med. 2011;29(5): 574.e5-574.e7. https://doi.org/10.1016/j.ajem.2010.05.020

75. Koch M, Sievert M, Iro H, Mantsopoulos K, Schapher M. Ultrasound in inflammatory and obstructive salivary gland diseases: Own experiences and a review of the literature. J Clin Med. 2021;10(16):3547. https://doi.org/10.3390/jcm10163547

76. Huang F, Caton R, Colla J. Point-of-care ultrasound diagnosis of acute sialolithiasis with sialadenitis. Clin Pract Cases Emerg Med. 2017;1(4):437-438. https://doi.org/10.5811/cpcem.2017.7.34907

77. Pniak T, Štrympl P, Staníková L, et al. Sialoendoscopy, sialography, and ultrasound: a comparison of diagnostic methods. Open Med (Wars). 2016;11(1):461-464. Published 2016 Nov 26. https://doi.org/10.1515/med-2016-0081

78. Hoffman HT, Pagedar NA. Ultrasound-guided salivary gland techniques and interpretations. Atlas Oral Maxillofac Surg Clin North Am. 2018;26(2):119-132. https://doi.org/10.1016/j.cxom.2018.04.001

79. Chung MK, Jeong HS, Ko MH, et al. Pediatric sialolithiasis: what is different from adult sialolithiasis? Int J Pediatr Otorhinolaryngol. 2007;71(5):787-791. https://doi.org/10.1016/j.ijporl.2007.01.019

80. Kim DH, Song WS, Kim YJ, Kim WD. Parotid sialolithiasis in a two-year-old boy. Korean J Pediatr. 2013;56(10):451-455. https://doi.org/10.3345/kjp.2013.56.10.451

81. Benson BW. Salivary gland diseases. In: White SC, Pharoah MJ, eds. Oral Radiology: Principles and Interpretation. 7th ed. Elsevier; 2014:chap 29.

82. Kraaij S, Karagozoglu KH, Forouzanfar T, et al. Salivary stones: symptoms, aetiology, biochemical composition and treatment. BDJ. 2014;217(11):E23. doi:10.1038/sj.bdj.2014.1054

83. Mostafavi Tabatabaee R, Mostafavi Tabatabaee R, Sanatkhani M. Salivary megaliths: a literature review of giant salivary sialoliths larger than 30 mm. J Pharm Res Int. 2019;29(4):1-17. https://doi.org/10.9734/jpri/2019/v29i430245

84. Nozhenko OA, Savchuk LA, Zaritska VI, et al. Phleboliths, not sialoliths: a report of submandibular gland arteriovenous malformation with numerous calcifications: analysis of cine images and literature review for the 54 years. J Diagn Treat Oral Maxillofac Pathol. 2023;7(7):63-86. https://doi.org/10.23999/j.dtomp.2023.7.1

85. Teymoortash A, Ramaswamy A, Werner JA. Is there evidence of a sphincter system in Wharton's duct? Etiological factors related to sialolith formation. J Oral Sci. 2003;45(4):233-235. https://doi.org/10.2334/josnusd.45.233

86. Beahm DD, Peleaz L, Nuss DW, et al. Surgical approaches to the submandibular gland: a review of literature. Int J Surg. 2009;7(6):503-509. https://doi.org/10.1016/j.ijsu.2009.09.006

87. Tymofieiev OO. Diseases of the Salivary Glands. VNTL-Klasyka; 2007. Ukrainian.

88. Savchuk LA, Fesenko II. Obstructive submandibular sialadenitis complicated with severe neck phlegmon: transcutaneous removal of sialolith with a flow of pus: literature review of extraoral complications. J Diagn Treat Oral Maxillofac Pathol. 2021;5(11):125-134. https://doi.org/10.23999/j.dtomp.2021.11.1

89. Markiewicz MR, Margarone JE 3rd, Tapia JL, Aguirre A. Sialolithiasis in a residual Wharton’s duct after excision of a submandibular salivary gland. J Laryngol Otol. 2007;121(2):182-185. https://doi.org/10.1017/s0022215106003525

90. Su LW, Sun H, Zhang HY, Wu Y. Large recurrent sialoliths in a residual Wharton duct after sialoadenectomy: Two case reports and literature review. Medicine (Baltimore). 2025;104(2):e41231. https://doi.org/10.1097/md.0000000000041231

91. Ahmed SS, Abid S, Al-Thobaiti Y, et al. Longstanding unrecognized wooden foreign bodies in oro-facial region, report of three cases. Am J Public Health Res. 2015;3(4):157-161. https://doi.org/10.12691/ajphr-3-4-5

92. Gill AS, Kieliszak CR, Joshi AS. Sialendoscopy as a management tool in patients with foreign body impaction of the salivary gland. Am J Otolaryngol. 2016;37(4):369-371. https://doi.org/10.1016/j.amjoto.2016.02.008

93. Zheng DN, Xu XY, Ling XT, Liu DG. Stensen’s duct penetration and sialolith formation: a rare complication of thread lifting surgery. J Stomatol Oral Maxillofac Surg. 2025;126(5S):102489. https://doi.org/10.1016/j.jormas.2025.102489

94. Luo WD, Jia YP, Gong J, Zhao Q. Unusual foreign body spontaneously discharged from the submandibular gland: A case report. J Clin Ultrasound. 2022;50(2):243-246. https://doi.org/10.1002/jcu.23045

95. Oz C, Kapi E, Erkan SO, Külahçi Ö. Etiology of a rare intraglandular foreign body in the parotid gland: Vegetable nidus. Turk J Plast Surg. 2022;30(3):76-78. https://doi.org/10.4103/tjps.tjps_12_22

96. Sato K, Umeno H. Clinical photographs. Fish bone-induced sialolith. Otolaryngol Head Neck Surg. 2009;141(4):539-540. https://doi.org/10.1016/j.otohns.2009.05.002

97. Yoshida M, Yamamoto K, Shimasue H, et al. A case of acute submandibular sialadenitis caused by a fish bone that strayed into the submandibular gland duct. Oral Sci Int. 2024;21(2):123-127. https://doi.org/10.1002/osi2.1217

98. Smith AB, Jones CD. Ultrasound diagnosis and sialadenectomy confirming a mandibular salivary gland vegetative foreign body and chronic sialadenitis in a dog. J Am Vet Med Assoc. 2024;264(3):112-115. https://doi.org/10.1016/j.javma.2026.01.002

99. Oliaei S. Are there ways to prevent salivary stones? Instagram. February 18, 2026. Accessed June 19, 2026. https://www.instagram.com/reel/DU6QOTaDGob/

100. Lee CC, Huang JC, Shin JS, Wu MJ. Tumefactive sludge mimicking gallbladder neoplasm: A case report and review of the literature. J Med Ultrasound. 2018;26(2):103-106. https://doi.org/10.4103/JMU.JMU_19_18

101. Bradley MJ. Salivary glands. In: Ahuja A, Evans R, eds. Practical Head and Neck Ultrasound. Greenwich Medical Media; 2000:ch 2.

102. Aoun G, Maksoud C. Sialolith of unusual size and shape in the anterior segment of the submandibular duct. Cureus. 2022;14(4):e24114. https://doi.org/10.7759/cureus.24114