Sialolith with Sialadenitis: A Case Study and a Proposal of a Diagnostic Algorithm

Abstract Sialolithiasis along with sialadenitis is one of the commonly occurring salivary gland disorders. Sialadenitis is an inflammatory disease of the salivary glands. It usually occurs insidiously causing pain to the patient and may lead to development of fibrous mass of the salivary gland. The cause of sialadenitis is most commonly due to the salivary duct caliculi which is termed as sialolith or salivary stones which causes statis of saliva in the ducts. This condition is usually accompanied by pain and tenderness of the involved site. Therefore, we report a case of a male patient aged 60 years with pain in the floor of the mouth in the submandibular region which was diagnosed as submandibular sialolithiasis along with sialadenitis and propose a diagnostic algorithm.


Introduction
Sialolithiasis occurs in approximately 1% of the general population.About 80 to 90% of salivary stones occur in submandibular gland. 1 The composition of sialolith can vary depending upon the concentrations of organic or inorganic components and the gland in which it has occurred.Submandibular gland sialoliths (SMGS) are usually composed of inorganic materials such as hydroxyapatite, brushite, and octacalcium phosphate. 2The formation of SMGS is not a single process, it is influenced by various factors such as stasis of saliva, changes occurring in the salivary biochemistry, and accumulation of calcium phosphate. 2The inflammation of the salivary gland is termed sialadenitis and it is an insidious disease usually affecting the major salivary glands and characterized by intermittent swelling, accompanied by pain and tenderness. 3The microbiology of sialadenitis is not much reported in submandibular and sublingual glands.Bacterial colonies such as staphylococcus, streptococcus, and Gram-negative bacteria are the most common etiologic factors to cause this inflammatory condition. 4ince the exact etiology is still unclear there are few theories considered for the formation of sialoliths: (1) sia-lomicroliths agglomerating together, (2) mucus plug getting calcified, and (3) alteration of the saliva's biochemical composition.The composition of the sialoliths can be assessed through various methods such as wet chemical techniques, X-ray powder diffraction, and/or Fourier-transform infrared spectroscopy (FTIR).The FTIR is the most commonly accepted method since it is rapid and easily reproducible.The concept of FTIR is that the IR spectrum initially begins from the vibration of molecules.These motions of molecules due to vibration produces frequencies which are unique to individual compounds similar to that of fingerprints.This can be utilized for the classification of organic and inorganic compounds present.Similarly, in wet chemical analysis the quantification of ions and organic components can be calculated. 5The most commonly accepted method for assessing the composition of lithiasis is wet chemical analysis method proposed by Larsson et al, 6 he had initially performed in urinary caliculi.The wet chemical method includes various steps such as: (1) Drying and dissolution: Initially, the calculus must be weighed and needs to be pulverized in a mortar and to be dried over silica gel to completely desiccate at room temperature for 2 days.(2) Later, 1 mL of concentrated nitric acid to be added to the powder, effervescence shows the presence of carbon.(3) Next, the calculus needs to be completely dissolved and kept in magnetic stirring for 3 hours at room temperature for creating the sample solution to find the presence of particular component such as calcium, magnesium, ammonium, phosphate, oxalate, and urate.The sample solution shouldn't be diluted for the analysis of cysteine and protein but for rest it needs to be diluted.(4) Result calculation: The molar concentrations and volume of sample solution can be used to evaluate the amount of analyte in µmol.The composition of calculus can be computed. 6e diagnosis of this disease is usually made clinically with conventional radiography such as orthopantomogram (OPG) or occlusal radiographs followed by surgical removal of the salivary stone and the gland involved. 5

Case Report Clinical Examination
A 60-year-old male patient presented with pain and swelling in the lower right side of the floor of the mouth for the past week.The history of pain was sudden in onset with moderate intensity and was continuous in nature.The patient did not state any aggravating or relieving factors.The patient also gave no relevant history about the change in the size of the mass.On extraoral examination, mild facial asymmetry was noted on the right side.On palpation of the right submandibular region, there was a diffused enlargement noted of approximately 2 cm Â 2 cm in size roughly along with tender and palpable lymph nodes.There was no difficulty in mouth opening and closing along with normal jaw moments.

Radiographic Examination
An OPG was taken (►Fig.1).The OPG revealed a well-defined radiopaque mass seen superimposed in the right lower body of the mandible near the angle of the mandible of size approximately 3.5 mm Â 1.7 mm in size and a provisional diagnosis of sialolith was considered.The patient was referred to the department of oral surgery for further management.

Surgical Intervention
The surgeons evaluated the patient and prepared for the removal of the sialolith along with the involved salivary gland.An excisional biopsy was performed and given for histological evaluation (►Fig. 2).

Histopathological Examination
The gross specimen was received for histopathological evaluation (►Fig. 3).A radiograph of the gross specimen was also taken to check for any other calcifications present within the gland (►Fig.4).On gross examination of the sialolith it roughly measured around 1.3 cm Â 0.9 cm in size (►Fig. 5).
The hematoxylin and eosin-stained section showed encapsulated lobules of the salivary gland which were seen separated by thin fibrous septa.Numerous seromucous acini were seen.One part of the section showed loss of architecture of the acini and a focal area of diffused infiltration of inflammatory cells into the gland along with numerous ducts.Periductal inflammation was also noted along with blood vessels and extravasated red blood cells (►Fig.6).

Discussion Sialolithiasis
Sialolithiasis is formation of salivary stones in the ducts of the major salivary glands: the parotid, submandibular, and sublingual glands with a reported prevalence of 1 in 10,000 to 1 in 30,000, and it is the most common cause of salivary gland enlargement. 7Sialoliths can occasionally restrict the salivary ducts, causing inflammation and root a secondary bacterial infection, or in extremely rare circumstances form an abscess.There are many presenting signs, but the two most prevalent signs are reduced salivary flow and cyclical   postprandial enlargement of the afflicted gland. 8The etiology and pathophysiology are presented as a flowchart (►Fig.7). 9,10

Sialadenitis
Sialadenitis is the inflammatory condition of salivary glands.It most commonly occurs in major salivary glands.Submandibular sialadenitis is usually caused due to stasis of saliva which in turn leads to retrograde seeding of bacteria from the oral cavity.Submandibular glands are present bilaterally in the submandibular triangle covered by the investing layer of deep cervical fascia and it drains into the oral cavity through the Wharton's duct in the floor of the mouth.The submandibular gland saliva is rich in potassium and low in sodium.There are two forms of submandibular gland sialadenitis: acute and chronic form.The acute form is characterized by insidiously occurring and the chronic form is characterized by long-standing infection due to obstruction.The usual clinical presentation will be swelling of the gland without erythema accompanied by pain.The common causes and pathophysiology are listed in ►Fig. 8. [11][12][13][14] Since there are numerous causative factors, all differential diagnosis must be excluded by the clinician based on the clinical criteria to arrive at a diagnosis.The clinical, radiographical, laboratory, and histological tests need to be done for confirmatory diagnosis.To assist the diagnostician in Fig. 7 Flowcharts showing the pathophysiology and etiology of sialolithiasis.
Fig. 8 Common causes and pathophysiology of sialadenitis.
reaching a diagnosis and course of treatment, we suggest a straightforward but practical diagnostic algorithm.This algorithm takes into consideration the palpable salivary stones as well [15][16][17][18] (►Fig.9).
The most common cause of sialadenitis is sialolithiasis, which occurs in the submandibular region and accounts for approximately 80% of cases. 19There are various theories put forth on the formation of salivary stones, but they are most likely to occur in the submandibular gland because of salivary stagnation, increased alkalinity of saliva, physical trauma, being more susceptible to infection and inflammation, and the production of saliva against gravity. 20Also, the contents of submandibular saliva contribute due to their increased levels of mucin, protein, calcium, and phosphate  compared to that of other major salivary glands. 19In fact, tobacco can also contribute to the formation of sialoliths because it greatly influences the rate of salivary flow and can also cause inflammation of the gland. 20About 85% of the sialoliths occur in Wharton's duct because of its complex morphology, while the rest, 15%, occur in the gland parenchyma. 20,21The obstruction of the gland can cause swelling with a subsequent risk of superinfection.Sialolith usually occurs predominantly in adult male population.In the current case report a 60-year-old male was affected which is in accordance to the literature. 21The signs and symptoms include cyclical episodes of pain accompanied by inflammation and swelling, the inflammation and swelling occur due to the obstruction of the flow of saliva, resulting in increased intraglandular pressure.In partial or incomplete ductal obstruction, the saliva can escape around the sialolith.In these types of cases, the patients will be asymptomatic and can only be diagnosed as an incidental finding in routine dental radiography. 22The imaging of the salivary gland is crucial because it aids in determining the location, kind, and extent of the lesion, assessing the ductal morphology, choosing the site of the biopsy, and formulating a treatment strategy. 23Conventional radiography, digital subtraction sialography, sonography, computed tomography, and magnetic resonance (MR) imaging sialography are imaging methods that can be used to investigate salivary calculi.Just 20% of calculi are radiopaque, and conventional radiography depends on the nature of the stone.Digital subtraction sialography has a sensitivity range of 96 to 100% and a specificity range of 88 to 91%.Because of the possibility for an infection's symptoms to worsen, it is contraindicated in the acute context.According to reports, sonography has a sensitivity range of 59.1 to 93.7% and a specificity range of 86.7 to 100%. 22,23According to reports, MR imaging sialography has a 91% sensitivity rate and a 94 to 97% specificity rate. 24he choice of imaging modality should be made based on the disease and the characteristics of the patient.There are numerous therapy options that principally rely on the sia-lolith's size and location.Frequently performed is bimanual palpation for tiny stones which pass through the duct and are "milked out."Surgical shock wave lithotripsy is advised for salivary stones up to 10 mm which have been found in the proximal part of the duct and it is an extremely minimal invasive procedure for removing substantial salivary stones.][17][18] The differentials that can be considered in case of swelling in the submandibular region and radiopacities seen in radiographs are listed out in ►Table 1.
The uniqueness of this case study is that it provides a detailed insight on sialolith in the submandibular gland; its etiology, pathogenesis, analysis and composition of salivary caliculi, and a diagnostic algorithm is proposed which can help the surgeons to manage sialoliths with sialadenitis more efficiently and contribute to the literature on the subject.The terms "sialolithiasis" and "submandibular gland sialolithiasis" were used in searches on PubMed and Google Scholar.Pertinent published articles in dentistry journals were reviewed and included in the current case report.Only English-language studies published after the year 2010 reporting cases of sialoliths with sialadenitis occurring in the submandibular gland among Indian population were chosen for the review and tabulated (►Table 2).

Conclusion
Sialoliths need to be assessed and managed properly prior to the involvement of the gland because sialadenitis can cause detrimental effects.A meticulous history collection and appropriate imaging techniques would preserve time.This case report adds to the literature, it illustrates a case of sialolithiasis occurring along with sialadenitis that was diagnosed clinically and interpreted using a simple radiograph and treated with no complications.A diagnostic algorithm has been proposed to arrive at a quick diagnosis and initiate a prompt treatment.

Fig. 2 (
Fig. 2 (A) Preop picture of the patient with marking prior to removal of the sialolith and the involved submandibular gland.(B) Postop picture of the patient after the removal of sialolith along with submandibular gland.

Fig. 4 X
Fig. 4 X-ray of the excisional biopsy of sialolith along with submandibular gland.

Fig. 6
Fig. 6 Photomicrograph of submandibular sialadenitis showing: (A) Lobules of gland with mixed seromucinous acini in lower power magnification.(B) Periductal inflammation with dense inflammatory infiltrate.(C) Infiltration of inflammatory cells into the gland.(D and F) Higher power image showing infiltration of inflammatory cells in between acini and ducts.(E) Destruction of the ducts by the inflammatory cells.

Table 1
25,26rential diagnosis that can be considered for swelling in submandibular region and radiopacities seen in radiographs25,26

Table 2
Cases of sialoliths occurring in submandibular gland reviewed in literature from the year 2010 to 2023 among the Indian population