The major salivary glands (parotid, submandibular, and sublingual) are most frequently obstructed by calculi within the salivary gland, or more uncommonly, by ranulas. Despite the well-defined clinical and radiographic diagnostic features, sialolithiasis may sometimes be confused with sialadenitis and ranulas, especially when encountered in general dental practice. We, therefore, present a case that illustrates this diagnostic dilemma to highlight the salient features of all three conditions. A 28-year-old female presented with a history of a submandibular swelling for 8 months. On intraoral examination, a bluish sublingual swelling was identified at the left side of the lingual frenum, causing a slight elevation of the tongue. The preliminary diagnosis was of a ranula; however, the clinical history suggested sialolithiasis. A hard structure was palpated in the submandibular gland, and a mandibular occlusal film revealed a large ductal sialolith. Sialolithotomy was performed under local anesthesia, and a single 7.2 mm stone was retrieved. The postoperative follow-up period was uneventful, with good healing and restored normal salivary flow. Despite the fairly clear clinical and radiographic diagnostic criteria suggestive of sialolithiasis, the bluish-tinged swelling of the floor of the mouth prompted the examining dentist to provisionally diagnose a ranula. Sialolithiasis is a common obstructive condition of the salivary gland encountered in the dental setting. Despite the clinical and radiographic features usually guiding the correct diagnosis, it can be a challenging diagnosis for less experienced dentists, who must always carefully consider the history, clinical, and radiographic findings.
Keywords: Ranula, sialadenitis, sialolithiasis, submandibular gland
| Introduction|| |
Obstructive salivary glands disorders can occur in any gland but are more frequently encountered in the major salivary glands such as the parotid, submandibular, and sublingual glands, more than in the minor salivary glands. A ranula is a submucosal retention cyst occurring in the sublingual salivary gland that develops through mucus extravasation through leakage from a sublingual duct. The term "ranula" originates from the Latin word rana, meaning frog because the consequent bulge resembles an underbelly of a frog. There are two types of ranula depending on its position in relation to the mylohyoid muscle: A simple ranula is usually sited above the mylohyoid, while a deep or plunging ranula occurs beneath the muscle tissue.
Ranulas usually present as painless swellings in the floor of the mouth that can interfere with mastication, speech, and swallowing. Large intraoral ranulas can also interfere with submandibular salivary flow to produce obstructive salivary gland signs and symptoms such as discomfort or pain during eating and submandibular gland swelling. While ranulas are usually recognized as a fluctuant, soft, slow-growing swellings with a bluish discoloration in the floor of the mouth, misleading symptoms, can obscure the diagnosis and prompt further investigations.
Sialolithiasis – calculi within the salivary glands or ducts – is one of the most common obstructive disorders of the major salivary glands, which represents 40%–60% and 70%–85% of all obstructive diseases that affect the submandibular and parotid glands, respectively. Sialolithiasis occurs in between 7 and 14 per 100,000 people each year, with no significant gender predilection., Sialoliths are condensations of mainly calcium phosphate (a minor component of ammonium and magnesium carbonate) often arising in the submandibular gland (64%), followed by the parotid gland (20%) and sublingual gland (16%). This preference for the submandibular gland might be due to the salivary flow running against gravity, the long tortuous structure of Wharton's duct, and the mucinous nature of the submandibular saliva with its relatively high calcium content. The submandibular stones can be found in the gland or the duct.
The clinical signs and symptoms of sialolithiasis are commonly encountered in dental practice. Salivary calculi obliterate the lumen of Wharton's duct, resulting in pain and swelling in response to salivary secretion, especially at mealtimes. Sialolithiasis is characterized by a relapsing-remitting clinical course. With large sialoliths, symptoms can be particularly severe. Lymphadenitis may occur in association with secondary recurrent ascending infection in the gland. Ductal stones may be palpable by bimanual palpation. Although the recent technological advances in sonography, sialography, sialoendoscopy, computed tomography, and magnetic resonance imaging have contributed to the diagnosis of sialoliths, the intraoral radiographs – especially occlusal views – remain a gold-standard diagnostic modality with a higher diagnostic yield than the extraoral radiographs. However, despite the well-defined clinical and radiographic diagnostic features, the diagnosis of sialolithiasis may sometimes remain ambiguous due to confusion between sialolithiasis, sialadenitis, and ranulas, especially when encountered in general dental practice. We, therefore, present a case that illustrates this diagnostic dilemma.
| Case Report|| |
A 28-year-old female was referred to the oral surgery clinic from a general dentist with a preliminary diagnosis of a ranula. She had an 8-month history of a submandibular swelling aggravated by eating, especially citrus foods, with pain radiating to the tongue. She reported changes in the size of the mass, sometimes associated with fever and extraoral swelling. The last attack occurred 2 weeks before presentation, and the symptoms had persisted.
Data from comprehensive medical and dental history-taking and physical and radiographic examinations were integrated to thoroughly assess the patient and confirm the diagnosis. Extraoral inspection and palpation of the face revealed the left submandibular swelling with palpable, tender, and mobile lymph nodes. On intraoral examination, there was a bluish sublingual swelling at the left side of the lingual frenum, slightly elevating the tongue [Figure 1]a. On bimanual palpation, the fluctuant swelling was tender, and a hard structure was palpated. The ostium of Wharton's duct was erythematous, and the salivary flow was reduced with a pale yellow discharge. Upon aspiration [Figure 1]b and [Figure 1]c, the microbiological investigation confirmed an infection in the salivary secretion. A mandibular occlusal film revealed an ovoid radiopaque mass related to the lower first molar and extending to the third molar, suggestive of a ductal sialolith [Figure 2].
|Figure 1: Bluish sublingual swelling at the left side of the lingual frenum (a), slightly elevating the tongue (b), Aspiration of the swelling revealed pale yellow fluid (c)|
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|Figure 2: Mandibular occlusal film revealing an ovoid radiopaque mass related to the lower first molar and extending to the third molar, suggestive of a ductal sialolith|
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Sialolithotomy was performed under local anesthesia with 2% lidocaine and 1:100,000 epinephrine through an incision in the floor of the mouth. A single 7.2 mm stone was retrieved, and the incision was sutured [Figure 3]. The patient was given antibiotics and nonsteroidal anti-inflammatory drugs. The postoperative follow-up period was uneventful, with good healing and restored normal salivary flow.
|Figure 3: Sialolithotomy was performed under local anesthesia, single 7.2 mm stone was retrieved, and the incision was sutured|
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Histopathological analysis revealed that the sialolith was ovoid formed from the concentric lamellar material [Figure 4]a. The surrounding salivary ductal epithelium was disrupted, and the adjacent tissue was infiltrated with neutrophil polymorphs [Figure 4]b.
|Figure 4: Histopathological analysis of the resected stone and small amount of surrounding salivary tissue. (a) Photomicrograph of an H and E-stained section (×40) of the calculus formed from the concentric lamellar material surrounded by an inflamed salivary duct, (b) Photomicrograph of an H and E-stained section (×100) showing the neutrophilic infiltrate around the stone and disruption of the salivary gland epithelium|
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| Discussion|| |
Despite submandibular salivary gland sialolithiasis presenting as one of the most prevalent disorders affecting the submandibular salivary glands, its diagnosis can be challenging for the inexperienced dental practitioner. Gritzmann et al. reported that localizing the stone is crucial for treatment planning, since ductal calculi require sialolithotomy, while glandular calcifications require the removal of the entire gland. In the present case, integrating the history with the clinical symptoms, bimanual digital palpation, and radiographic information guided the final decision of sialolithotomy by properly localizing the stone within the duct.
As advocated by others, the intraoral occlusal radiographs provided better imaging information than the extraoral imaging in the present case. Indeed, the occlusal film was the main tool used to localize the stone and estimate its size. Lustmann et al. further emphasized that stones can be superimposed on teeth or bony structures in the extraoral radiographs; hence, care must be taken in their interpretation.
The etiology of sialolith formation is multifactorial and still ambiguous. However, the majority are thought to arise from mineralization around a nidus of a mucus plug, epithelial cells, or foreign bodies, sometimes in association with a stagnation of salivary secretions. The local presence of bacteria in the oropharynx may explain its association with the clinical signs of sialadenitis. This is consistent with the current case, where the patient reported periods of acute symptoms of inflammation, infection, and pain that rapidly remitted with antibiotic therapy.
Drage et al. reported that the submandibular salivary gland duct is more frequently involved than the hilum of the gland. Furthermore, Pizzirani et al. recorded a higher prevalence of calculi in the left submandibular gland, consistent with our case.
Despite the fairly clear clinical and radiographic diagnostic criteria suggestive of sialolithiasis, the bluish-tinged swelling of the floor of the mouth prompted the examining dentist to provisionally diagnose a ranula. Had there not been meticulous clinical examination and referral notes a differential diagnosis would have been missed. This uncertainty has previously been reported in the literature. The relapsing-remitting course misdirected the dentist to consider the retention cystic behavior of the ranula rather than the associated inflammatory symptoms. The partial blocking of the duct by the relatively large stone added to the confusion.
| Conclusions|| |
Sialolithiasis is one of the most common obstructive conditions of the major salivary gland encountered in the dental settings. Despite the clinical and radiographic features usually guiding the correct diagnosis, it can be challenging for less experienced dentists, who must always carefully consider the history, clinical, and radiographic findings.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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Sahar M.N. Bukhary,
Department of Oral Biology, Faculty of Dentistry, King Abdulaziz University, Jeddah
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]