|Year : 2023 | Volume
| Issue : 5 | Page : 91-94
Atypical variant of Stafne bone defect mimicking odontogenic cyst of the jaw
T Manigandan, Rakshanaa T. V Rajalakshmi, Pavani Dornadula
Department of Oral Medicine and Radiology, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research, Chennai, Tamil Nadu, India
|Date of Submission||10-Jun-2022|
|Date of Decision||09-Aug-2022|
|Date of Acceptance||18-Aug-2022|
|Date of Web Publication||04-Feb-2023|
Department of Oral Medicine and Radiology, Sree Balaji Dental College and Hospital, Bharath Institute of Higher Education and Research, Narayanapuram, Pallikaranai, Chennai - 600 100, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Stafne first described the term “Stafne bone defects” (SBDs) in 1942. These are unilateral, asymptomatic, well-defined radiolucent lingual bony defects located at the posterior region of the mandible below the inferior alveolar canal. It is most commonly seen in the posterior region, whereas it is relatively rare in the anterior region. This anterior variant of SBD is often misdiagnosed as any other odontogenic cyst, and hence advanced imaging techniques should be followed to identify it at the earliest. Due to the lower prevalence of this entity, only a handful of cases have been documented for the anterior variant of SBD. In this paper, we have thus documented the rare variant of SBD in the anterior region.
Keywords: Anterior variant, CBCT, MRI, radiolucency, Stafne bone cyst, Stafne bone defect
|How to cite this article:|
Manigandan T, Rajalakshmi RT, Dornadula P. Atypical variant of Stafne bone defect mimicking odontogenic cyst of the jaw. J Oral Maxillofac Pathol 2023;27, Suppl S1:91-4
|How to cite this URL:|
Manigandan T, Rajalakshmi RT, Dornadula P. Atypical variant of Stafne bone defect mimicking odontogenic cyst of the jaw. J Oral Maxillofac Pathol [serial online] 2023 [cited 2023 Mar 21];27, Suppl S1:91-4. Available from: https://www.jomfp.in/text.asp?2023/27/5/91/369170
| Introduction|| |
Stafne bone defect (SBD) was initially characterised as a bony depression seen in the mandible that is reported to be filled with soft tissue such as salivary gland tissue, fatty tissue, blood vessels, lymphoid tissues and nerve bundles, etc. Stafne bone defect usually is asymptomatic and in most cases, it becomes an incidental finding on a routine radiographic examination of the mandible. Till date, SBDs are being documented with various terms such as Stafne defect, Stafne's idiopathic bone cavity, Stafne bone defect, Stafne bone cyst, latent bone cyst, lingual mandibular cortical defect, lingual mandibular salivary gland depression, or static bone cyst.
This bone defect is said to be developmental, and there are so many debates regarding whether this defect is developmental or congenital. Several literatures reported that it is not present at the time of birth which indicates that it occurs in the later stage of life. These bone defects are typically located in the submandibular gland fossa (posterior variant), associated with the submandibular glands, and they are rarely seen near the periapical region of the premolars, associated with the sublingual glands (anterior variant). Whenever SBDs have been reported in literature, they commonly refer to the posterior variant, since the anterior variant is rarely reported. This article documents a case of anterior variant of SBD, an uncommon variant.
| Case Description|| |
A 52-year-old woman reported for regular dental check-up and was referred to our outpatient department by a private practitioner for surgical management of a radiolucent lesion in the right lower jaw, which was noticed in the routine radiographic examination and was assumed to be a periapical cyst. The patient's medical and dental history were not significant and non-contributory. On clinical examination, the patient was asymptomatic and no extraoral abnormalities were noticed. On Intraoral examination, there was no evidence of any dental pathology in the right lower back tooth region. On palpation, there was no tenderness and no loss of integrity in the bone level. Vitality test revealed that all teeth were vital in that region. The orthopantomogram (OPG), taken previously, revealed a well-circumscribed, unilocular, ovoid radiolucency with a sclerotic border in relation to the lower right premolar region [Figure 1] which appeared to be superimposing the teeth roots; but the periodontal ligament is not continuous with the lesion. The radiolucent area seemed to be unrelated to the tooth. Hence the patient was advised to undergo cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI), for further evaluation of that region.
|Figure 1: Panoramic radiograph showing radiolucent lesion in lower right premolar region|
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CBCT [Figure 2] revealed a well-defined depression of lingual cortex seen on the lower right premolar region extending superiorly from the middle third of the premolar and inferiorly up to the apical third of the premolar. MRI [Figure 3] revealed a bony cavity filled with soft tissue invagination at the lingual cortical bone similar to glandular tissue. Based on the clinical and radiographical findings, a diagnosis of anterior variant of Stafne bone defect (ASBD) was given, which is rarely reported with a prevalence rate of 0.009%–0.03% in the literature. Further surgical intervention was deferred and the patient was informed about the normal variation.
|Figure 2: CBCT showing lingual bony defect in the lower premolar region. (a) Para-sagittal view (b) Coronal view (c) Axial view|
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|Figure 3: MRI in three planes (a) sagittal view (b) coronal view (c) axial, T2-weighted image shows a lingual bony cavity in the anterior part of the mandible which is filled with iso-intense soft tissue that is identical in signal with that of the salivary gland|
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| Discussion|| |
Stafne bone defect is a rare developmental anomaly which is usually seen between the age group of 11 and 30 years. The 12 SBDs reported by Minowa et al. were in patients aged 18–64 years (mean age 57 years). A strong male predilection was observed in these cases. In a study by Assaf et al., a total of 11 cases indicative of stafne bone defect (SBD) fulfilled the diagnostic criteria, among which all were men (100%) with a male-to-female ratio of 11:0. Morita et al. reported that SBDs were more frequently observed in men (70%) than in women (30%). Philipsen et al. showed a 6:1 male-to-female ratio for SBDs. Koç et al. reported that 7.14% of SBDs were found in a female and 92.86% were found in 13 males.
The prevalence of posterior variant of SBD is 0.10%–0.48%, and anterior variant of SBD is very rare with a prevalence of 0.009%–0.03%., The anterior variant is reported to be seven times less common than the posterior variant. Turkoglu et al. reported that the prevalence of anterior variant was predominant in men with a ratio of 3:1 (70%) and the age ranged from 18 to 68 years. They are often confused with periapical lesions and present as unilocular radiolucencies at the periapical area of the incisor, canines, or premolars. In the absence of caries in the teeth and mild root resorption, SBDs should also be considered as differential diagnosis. In cases of biopsy of the anterior variant, it often reveals salivary gland tissue originating from the sublingual gland.
The aetiopathogenesis of SBDs is said to be as “glandular hypothesis” which states that major salivary glands that have hyperplastic or hypertrophic lobes exert pressure on the buccal and lingual cortex of that mandible that leads to bone resorption resulting in bony cavity or defect. This shows the reason for posterior variant if the defect is present in the permanent molar region and anterior variant if the defect is present in-between permanent incisors to premolar region. There are four types of SBDs based on the location: lingual anterior, lingual posterior, lingual ramus, and buccal ramus. Based on the extent of the defect, it is classified into three types [Figure 4]. In type I, the bottom of the bone defect does not reach the buccal cortex. In type II, the bottom of the defect reaches the buccal cortex without any expansion. In type III, there is evidence of expansion of the buccal cortex. In our case report, it was a type of lingual anterior variant in relation to lower right premolar region with type I defect. Other than these types, there has been single or multiple SBDs in same side, unilateral, or bilateral defects reported in literatures.
|Figure 4: Types of Stafne bone defect based on extent. In type I, the defect does not reach buccal cortex, in type II, the defect reaches the buccal cortex without expansion, and in type III, defect led to expansion of cortex wall|
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Usually, SBDs have been an incidental finding in a routine radiographic examination. With two-dimensional radiographs, it is easier to diagnose the posterior variant of SBD when compared to the anterior variant, since the anterior variants may be present in-between the roots, resembling a cyst or a tumour which is often misdiagnosed. The differential diagnosis of SBDs can be benign salivary gland tumours, fibro-osseous lesions, neurogenic tumours, haemangioma, odontogenic cyst, simple bone cyst, myxoma, central giant cell lesion, ameloblastoma, multiple myeloma, eosinophilic granuloma, and metastatic disease. In such cases, as further investigation, advanced imaging techniques such as CBCT, MRI, sialography would be required for proper diagnosis. However, there are reports where sialography turned out to be negative in surgically proven SBD cases, and hence it is not a much reliable technique.
MRI allows the detailed differentiation of such soft tissues, with an advantage that the patient is not exposed to ionizing radiation. However, the drawback of MRI is that it is not cost-efficient and it causes artefacts in patients with any fixed prosthesis or orthodontic devices. Recently, CBCT examination has become more common in dentistry and is more accessible when compared to other imaging modalities for dentistry. Hence, proper imaging modalities are required to prevent any misdiagnosis.
In our case, OPG was initially taken by a private practitioner showing a well-defined radiolucent lesion extending from 44 to 45 that made them arrive at a diagnose of periapical cyst. However, the lesion was not found to be arising from the root apex, and hence for further investigation CBCT was advised. CBCT revealed a lingual bony defect in relation to the lower right premolar region. Yet OPG and CBCT were not sufficient to arrive at a confirmatory diagnosis regarding the contents of the bone cavity, so MRI was taken. MRI further revealed that the bone cavity was filled with a soft tissue which was similar to that of a glandular tissue, providing a definitive diagnosis. Hence, we could exclude the cysts and tumours of the jaw from the differential diagnosis and arrive at a final diagnosis of SBD. This timely diagnosis with the help of advanced radiological imaging modalities, unnecessary surgical intervention was deferred, and the patient was informed about the normal variation.
| Clinical Significance|| |
The rarity of anterior variant of SBD makes it challenging and sometimes may be missed or may erroneously be misdiagnosed. Timely diagnosis may prevent any misdiagnosis and defer unnecessary surgeries. This case report holds an immense significance of documenting a rare case of anterior variant of SBD and is reported in a female patient, which according to the previous literatures, is very uncommon.
| Conclusion|| |
Anterior variant of SBD being a rare type poses diagnostic dilemma due to its location and similar resemblance with cysts of the jaw. Routine radiographs do not provide much information in such cases; that makes it necessary to go for advanced imaging techniques to determine a final diagnosis. Knowledge on the common radiographic imaging features of SBD can help dental practitioners with a differential diagnosis of SBD. Thorough clinical examination, vitality test of the teeth, advanced imaging modalities, and tissue biopsy may be required to arrive at the final diagnosis.
Declaration of patient consent
The authors of this paper certify that we have obtained appropriate consent from the patient for the radiographic images for reporting to a journal for publication. The patient understood that their names and initials will not be published.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]