Traumatic Bone Cyst Of The Anterior Mandible: A Case Report

Traumatic bone cyst (TBC), also referred to as simple bone cyst or solitary bone cyst, is a non-neoplastic intraosseous cavity of the jaws characterised by the absence of epithelial lining, thereby classifying it as a pseudocyst rather than a true odontogenic cyst [1]. It predominantly affects young individuals and is most frequently discovered incidentally during routine radiographic examination due to its asymptomatic nature [2]. Radiographically, TBC typically presents as a well-defined unilocular radiolucency, often demonstrating scalloping between the roots of vital teeth with minimal cortical expansion [3]. Although the mandibular body is the most commonly affected site, anterior mandibular involvement has been reported and may present with variable imaging characteristics [4]. The etiopathogenesis remains uncertain, with trauma-induced intraosseous hematoma being the most widely accepted hypothesis [5].

Odontogenic keratocyst (OKC), a developmental odontogenic cyst arising from dental lamina remnants, is known for its medullary growth pattern, potential for cortical thinning or perforation, and tendency for recurrence [6]. Radiographically, OKC may appear as a well-defined unilocular or multilocular radiolucency and can extend extensively in an anteroposterior direction with minimal early buccolingual expansion. Due to overlapping imaging features such as well-defined borders and fluid density characteristics, differentiation between TBC and OKC based solely on radiographic findings can be challenging. Advanced imaging modalities such as cone-beam computed tomography (CBCT) aid in evaluating cortical integrity and lesion extent; however, definitive diagnosis ultimately relies on histopathologic confirmation.

CASE REPORT

A 12-year-old male patient presented to the Department of Oral Medicine and Radiology  with a chief complaint of malaligned lower anterior teeth. Clinical examination revealed lower anterior crowding, and the patient was subsequently referred to the Department of Orthodontics for further evaluation and management.

As part of routine orthodontic diagnostic records, an orthopantomogram (OPG) and a lateral cephalogram were advised. On panoramic examination, an incidental, well-defined radiolucent lesion was identified in the anterior mandible extending from the 34 to 44 regions.

The patient’s medical and dental history was non-contributory. Extraoral examination revealed no facial asymmetry, swelling, or palpable lymphadenopathy.

Figure 1A: Extraoral photograph showing absence of facial asymmetry or visible swelling.

Figure 1B: Intraoral photograph demonstrating normal overlying mucosa in the anterior mandibular region without evidence of cortical expansion or mucosal changes

Figure 2: Panoramic radiograph demonstrating a well-defined unilocular radiolucency in the lower anterior region

Figure 3: Cone-beam computed tomography images of the anterior mandibular lesion.
(A) Axial section demonstrating thinning of the labial and lingual cortical plates with focal labial cortical breach. (B) Coronal section showing marked thinning of the inferior mandibular border without root resorption. (C) Sagittal section illustrating significant anteroposterior medullary extension of the lesion.

Based on the radiographic features — including lesion size, medullary anteroposterior extension, cortical thinning with focal perforation, and absence of significant scalloping — a provisional radiographic diagnosis of odontogenic keratocyst was considered. Radiographic differential diagnoses included central giant cell granuloma, aneurysmal bone cyst, however, the imaging characteristics were less consistent with these entities.

Surgical exploration of the lesion was performed. Intraoperatively, an empty cavity was encountered without evidence of cystic epithelial lining. Curettage was carried out to induce bleeding and promote bone regeneration. Histopathological examination confirmed the absence of epithelial lining, establishing the final diagnosis of traumatic bone cyst.

DISCUSSION

Traumatic bone cyst (TBC) is an uncommon intraosseous pseudocyst of the jaws, predominantly affecting young individuals and frequently detected as an incidental radiographic finding [1,2]. It most commonly involves the mandibular body and typically presents as a well-defined unilocular radiolucency with scalloping between roots of vital teeth and minimal cortical expansion [2,4]. The present case is noteworthy for its occurrence in the anterior mandible of a 12-year-old male, with significant cortical thinning and a focal labial cortical breach—features not routinely associated with classic presentations of traumatic bone cyst.

The aetiology of TBC remains uncertain, although trauma-induced intramedullary hematoma with subsequent failure of clot organisation has been widely proposed [5]. Despite this hypothesis, many patients do not report a clear history of trauma, reinforcing the enigmatic nature of the lesion. Radiographically, TBC is generally described as a passive cavity with limited expansion and intact cortical boundaries [2]. However, atypical presentations with cortical thinning and occasional perforation have been documented, particularly in larger lesions [4]. In the present case, the lesion demonstrated considerable anteroposterior medullary extension, inferior border thinning, and labial cortical breach, thereby deviating from the classic radiographic description and contributing to diagnostic ambiguity.

Traumatic bone cysts typically demonstrate a characteristic scalloping pattern between the roots of adjacent teeth due to their tendency to extend along the cancellous bone without causing significant cortical expansion [2,4]. In the present case, distinct scalloping between the roots was not evident despite the lesion extending across multiple teeth. The absence of this classical feature, along with significant medullary extension and focal cortical breach, contributed to the provisional radiographic impression of odontogenic keratocyst, which is known to exhibit anteroposterior medullary spread with minimal early buccolingual expansion [3,6].

Central giant cell granuloma (CGCG), aneurysmal bone cyst (ABC), were considered in the differential diagnosis based on the patient's age and anterior mandibular location. CGCG commonly affects younger individuals and may involve the anterior mandible; however, it typically demonstrates expansile growth, multilocularity, root resorption, or tooth displacement, which were not observed in the present case.

ABC is characterized by rapid enlargement, pain, and marked buccolingual cortical ballooning with a multilocular “soap-bubble” appearance; the absence of significant clinical swelling, multilocularity, and aggressive expansion made ABC unlikely.

The lesion instead exhibited predominant medullary extension with cortical thinning and focal perforation, findings that more closely resembled odontogenic keratocyst radiographically. Definitive diagnosis was established only after histopathological confirmation of absence of epithelial lining, consistent with traumatic bone cyst.

Recent advances in radiographic interpretation and artificial intelligence–assisted imaging analysis have emphasized the diagnostic complexity of differentiating simple bone cyst from odontogenic keratocyst and other radiolucent jaw lesions based solely on imaging features [8]. Contemporary studies have demonstrated that although internal architecture, lesion contour, and cortical behavior may provide important diagnostic clues, substantial radiographic overlap persists, particularly in atypical presentations [9,10]. While traumatic bone cyst is generally described as a non-expansile, well-defined radiolucency with scalloping and intact cortical boundaries, larger lesions may demonstrate cortical thinning and occasional perforation, thereby simulating more biologically active entities [10]. Furthermore, recent case reports have highlighted that anterior mandibular involvement in young patients can present diagnostic ambiguity when classical radiographic features are absent [11]. In the present case, the combination of significant anteroposterior medullary extension, inferior border thinning, and focal cortical breach created a radiographic profile more suggestive of odontogenic keratocyst, underscoring the potential for misinterpretation. This case reinforces the growing consensus that despite advancements in CBCT and imaging analytics, histopathological confirmation remains indispensable in establishing a definitive diagnosis of radiographically deceptive jaw lesions [12].

Advanced imaging with CBCT in this case provided a detailed assessment of cortical integrity and lesion dimensions, demonstrating internal density suggestive of fluid content. Nevertheless, despite high-resolution imaging, a definitive distinction between TBC and OKC remained uncertain preoperatively. This reinforces the concept that radiographic evaluation, although critical, may not always be sufficient for conclusive diagnosis, and histopathological confirmation remains the gold standard [1,2].

The rarity of this case lies not merely in the diagnosis of traumatic bone cyst, but in its atypical radiographic behaviour mimicking an odontogenic keratocyst in the anterior mandible of a young patient. Such presentations underscore the importance of comprehensive radiologic evaluation and careful correlation with clinical and histopathologic findings. Awareness of these atypical imaging patterns is essential to avoid misdiagnosis and overtreatment.

CONCLUSION

Traumatic bone cyst is a rare pseudocyst of the jaws that is frequently discovered incidentally and typically presents with minimal clinical findings. However, atypical radiographic features such as significant medullary extension, cortical thinning, and focal cortical perforation may closely resemble odontogenic keratocyst, creating diagnostic uncertainty. The present case highlights the potential for a traumatic bone cyst to radiographically mimic a more biologically active lesion in the anterior mandible of a young patient. Although advanced imaging modalities such as CBCT provide a detailed assessment of lesion extent and cortical integrity, definitive diagnosis ultimately depends on histopathological evaluation. Awareness of such uncommon presentations is essential for accurate diagnosis and appropriate management while avoiding overtreatment.

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