Journal of Indian Academy of Oral Medicine and Radiology

: 2017  |  Volume : 29  |  Issue : 1  |  Page : 53--55

Simple bone cyst presenting as an incidental finding in pretreatment orthodontic radiograph: A case report

Salini G Sudha, Sunila Thomas, Vivek Velayudhan Nair 
 Department of Oral Medicine and Radiology, PMS College of Dental Science and Research, Vattappara, Trivandrum, Kerala, India

Correspondence Address:
Vivek Velayudhan Nair
Department of Oral Medicine and Radiology, PMS College of Dental Science and Research, Vattappara, Trivandrum  -  695  028, Kerala


Pretreatment radiographs, especially panoramic and lateral cephalometric are routinely used as an aid in orthodontic diagnosis and treatment planning. Sometimes abnormalities may be detected as incidental findings in such radiographs that require medical or odontological management. Simple bone cyst is an uncommon lesion mostly occurring in young individuals; it is often asymptomatic and accidently discovered during routine radiological examination. Mostly the pathology presents as a unilocular radiolucency in the mandible between canine and third molar. A definite diagnosis is invariably achieved during surgery as it presents as an empty cavity without lining. We present a case of a simple bone cyst of the body of mandible identified during routine pretreatment orthodontic radiograph.

How to cite this article:
Sudha SG, Thomas S, Nair VV. Simple bone cyst presenting as an incidental finding in pretreatment orthodontic radiograph: A case report.J Indian Acad Oral Med Radiol 2017;29:53-55

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Sudha SG, Thomas S, Nair VV. Simple bone cyst presenting as an incidental finding in pretreatment orthodontic radiograph: A case report. J Indian Acad Oral Med Radiol [serial online] 2017 [cited 2022 Jan 26 ];29:53-55
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Full Text


Simple bone cyst (SBC), first described by Lucas and Blum is an uncommon nonepithelium lined cavity of jaws, observed in the second decade with no gender predilection, and is often located in the mandible between canine and third molar.[1],[2] Most SBCs are diagnosed during an unrelated radiographic investigation such as orthodontic pretreatment radiograph. Literature suggests that 8.7% of orthodontic patients show evidence of pathology in radiograph.[3] A case of SBC discovered accidently during routine pretreatment orthodontic radiography is presented here.

 Case Report

A 16-year-old male patient with complaints of proclination and malalignment of anterior teeth was referred to the Department of Oral Medicine and Radiology from the Department of Orthodontics for routine panoramic and lateral cephalometric radiographs as part of orthodontic treatment. The panoramic radiograph showed an incidental finding of a well-defined, unilocular radiolucency measuring approximately 2 × 2.5 cm with sclerotic borders in the body of mandible in relation to 45 and 46 [Figure 1]. Anteroposteriorly, the lesion extended from the mesial radicular outline of 45 to 3 mm beyond the distal root outline of 46. Superoinferiorly, it extended from an area approximately 8 mm short of alveolar crest of 45 and 46 to 6 mm short of the inferior border of mandible, overlapping and scalloping in between the roots of 45 and 46. There was no displacement or resorption of adjacent teeth. Lamina dura was intact around the adjacent teeth. As the radiolucency was an incidental finding, the patient was subjected to detailed clinical examination. The patient was clinically asymptomatic and did not recall any history of trauma. Medical history was noncontributory. On examination, Angle’s class 1 molar relation with proclination of maxillary anteriors and crowding of mandibular anteriors were noted. Both the lower canines were rotated. Expansion of neither buccal nor lingual cortical plates were noted in 44, 45, 46, 47 region [Figure 2]. Overlying mucosa appeared normal. Pain, paresthesia, swelling, and mobility of teeth were not seen in the region. All the four teeth were vital to electrical pulp testing. Lymph nodes were not palpable.{Figure 1}{Figure 2}

Additional radiographic views (Intraoral periapical radiograph and lateral occlusal views) confirmed the orthopantomograph findings [Figure 3]. Mandibular occlusal radiograph did not show expansion of buccal and lingual cortical plates in 44, 45, 46, 47 region [Figure 4]. Aspiration of the lesion yielded only air. Considering clinical and radiographic features, a provisional differential diagnoses of SBC, keratocystic odontogenic tumor, and unicystic ameloblastoma were considered.{Figure 3}{Figure 4}

The lesion was managed by surgical exploration and curettage under local anesthesia in the Department of Oral and Maxillofacial surgery, PMS College of Dental Science and Research. The contents were sent for histopathologic examination (HPE). HPE revealed moderately collagenous connective tissue exhibiting fibroblast and a few blood vessels. Trabeculae of vital bone was seen with intervening delicate connective tissue, along with extravasated RBCs and fibrin. There was no evidence of lining epithelium [Figure 5]. Histopathologic findings were consistent with SBC. The healing was uneventful, and subsequent radiographs taken after 3 months indicated new bone formation.{Figure 5}


SBCs, also known as hemorrhagic bone cyst, solitary bone cyst, traumatic bone cyst, extravasation cyst, progressive bone cavity, unicameral bone cyst, and idiopathic bone cavity, are generally asymptomatic and are often incidental findings, as the present case.[2],[4] The patient was asymptomatic and was unaware of such a lesion until its discovery. Pain has been reported by 10–30% patients.[5] Other reported symptoms include tooth sensitivity, paresthesia, fistulas, delayed eruption of permanent teeth, displacement of inferior dental canal, and pathologic fracture of the mandible.[2]

Etiology of SBC is still unclear. However, the most widely accepted etiology is trauma leading to intraosseous hematoma, which later liquefies, and adjacent bone being destroyed by enzymatic activity, ultimately leading to cavitation of bone.[2],[6] Trauma can also initiate a subperiosteal hematoma that can compromise blood supply to the area leading to osteoclastic bone resorption.[2] In the present case, the patient was not able to recall any previous traumatic episode. However the possibility of a subclinical trauma could not be ruled out.

Radiographically SBC is described as well-defined corticated radiolucency with scalloped margins in between roots of teeth.[7] SBC has a tendency to grow along the long axis of the bone causing minimal expansion. However, larger lesions causing expansion and thinning of inferior cortex have been reported.[4] Displacement and resorption of adjacent teeth, if present, was minimal. Expansion and erosion of cortical plate; radiopaque foci within lesion; absence of cortical outline; root resorption and tooth displacement even though rare, have also been reported.[2],[8] In the present case, the radiographic appearance was that of a well-defined radiolucency with scalloping between the roots of adjacent teeth and with no expansion of the cortical plate. There was no resorption or displacement of adjacent teeth.

Aspiration of the lesion yielded only air. SBCs when discovered early contain blood or serosanguinous fluid, which diminishes with time, and eventually the lesion becomes empty.[2] Careful curettage of the lesion favors progressive bone regeneration offering good prognosis. Failure to detect the lesion may lead to complications such as pathologic fracture of mandible.

Literature suggests that the obliteration of defect by the new bone is generally rapid after surgery with or without curettage. Even large defects may show normal radiographic findings within 3–12 months of exploration.[4],[9] In the present case managed by surgical exploration and curettage, follow-up radiograph after 3 months indicated bone regeneration.

Radiographs are useful for forecasting the prognosis of SBC lesions. Lesions with intact lamina dura, smooth margins, and no expansion heal after surgery whereas those with absent lamina dura, root resorption, and nodular expansion tend to recur.[7],[10] Considering the incidental radiographic finding and rapid regeneration of the bone following surgical exploration, careful evaluation of pretreatment orthodontic radiographs are mandatory not only from an orthodontic perspective but also from the perspective of early diagnosis.


In the present case, because the condition was asymptomatic, radiolucency seen in panoramic radiograph was the only clue for diagnosis. Hence, a systematic approach for interpreting radiographs is recommended for the diagnosis of innocuous conditions.

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Conflicts of interest

There are no conflicts of interest.


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