Unusual bilateral dentigerous cysts in a nonsyndromic patient assessed by cone beam computed tomography.

In the absence of syndromes, bilateral dentigerous cysts (DC) located on the jaws are unusual. In English based language literature review, we only found eight reports of nonsyndromic bilateral dentigerous cyst associated with mandibular third molars. Therefore, we report the unusual occurrence of sizable nonsyndromic bilateral DC associated with mandibular impacted third molars in a 42-year-old Caucasian woman. The lesions were assessed by cone beam computed tomography (CBCT) the right lesion showed approximately 23.64 mm and the left one, 16.57 mm diameter, both located intimately next to the mandibular canal. Bilateral surgical enucleation, related teeth excision of both third molars and plate for fixation placement on the right and bigger lesion, under general anesthesia was the final treatment choice. Clinical, radiographic and histopathological features confirmed diagnose of bilateral dentigerous cyst. Now-a-days, the patient is on 18 months radiograph follow-up with favorable osseous formation with no evidence of recurrence of the cysts.

Introduction

Most dentigerous cysts (DC) are unilateral, accounting for approximately 24% of all true cyst in the jaws,[1] while bilateral and multiple cysts are unusual and occur typically associated with syndromes.[2] In English based language literature review, we only found eight reports of nonsyndromic bilateral DC associated with mandibular third molars.[23456789] Therefore, we report the unusual occurrence of nonsyndromic bilateral DC associated with mandibular impacted third molars.

Case Report

A 42-year-old Caucasian woman was referred for the evaluation of two bilateral asymptomatic, cystic lesions in the mandible. It was an incidental radiograph finding of unknown first appearance and evolution. Intraoral examination revealed clinically absent third molar teeth with no swelling or tenderness [Figure 1]. The medical history was nonsignificant and there were no association with syndromes.

Figure 1

Intraoral examination with no clinical signs: No swelling, no tenderness, normal color mucosa and clinically absent third molar teeth at the region, bilaterally. (a) Right side. (b) Left side

In cone beam computed tomography (CBCT), it was shown two well-defined unilocular radiolucent areas surrounded by thin sclerotic border related to unerupted mandibular molars. The one on the mandible right side showed diameter of approximately 23.64 mm and almost reached the inferior border and the left one 16.57 mm. Both third molars were displaced, the right one more grossly and apparently involving the distal root of the second molar and were located intimately with the mandibular canal [Figure 2].

Figure 2

On cone beam computed tomography panoramic (a) Axial (b) and sagittal (c and d) reformations was showed two well-defined unilocular radiolucent areas surrounded by thin sclerotic border associated to third molars displacement. On the right side, it has 23.64 mm diameter (c) and on the left side it has 16.57 mm diameter (d)

Surgical marsupialization and aspirative punctuation of the bigger lesion on the mandible right side was performed to attempt a bone formation. Three months later, no relevant new bone formation was observed. Therefore, surgical enucleation of both cysts was selected as treatment. Routine blood and urine tests were advised before the surgery and the results were within the normal limits. Under general anesthesia, the two cysts were enucleated together with the excision of the associated third molars and due to the lesion size and localization it was placed a plate for fixation to avoid postoperative fracture [Figure 3].

Figure 3

Transoperative clinical images (a) right side where we can notice the big cavity surrounding the impacted tooth and the fixation plate positioned on the mandibular ramus. (b) Left cavity

The histopathological examination of the left lesion revealed a cyst cavity lined by nonkeratinized, stratified, squamous epithelium of varying thickness [Figure 4a]. Underlying, in the cyst wall, sparse mononuclear inflammatory cells were observed. In addition, the right lesion showed epithelial hyperplasia of the cyst lining and capsular connective tissue with areas of intense chronic inflammation [Figure 4b]. Based on clinical, radiographic, and histopathological features the final diagnosis of dentigerous cyst was confirmed in both lesions. Now-a-days, the patient is on 18 months radiograph follow-up with favorable osseous formation with no evidence of recurrence of the cysts [Figure 5].

Figure 4

Histopathological findings showing the left cystic lesion lined by nonkeratinized, stratified, squamous epithelium of varying thickness (a) and the right lesion composed of hyperplasic epithelium and areas of intense chronic inflammation in the cyst wall (b)

Figure 5

Two months postoperative panoramic showing the fixation plate on right mandibular ramus and bone formation of both cavities

Discussion

Dentigerous cysts can be defined as a cyst that expands the follicle enclosing the crown, attached to the cementoenamel junction of an unerupeted tooth, account for approximately 24% of all true cyst in the jaws.[110] Although, they are common developmental cyst, reported bilateral DC are quite rare. They have rarely been reported and are usually associated with developmental syndromes such as the Maroteaux-Lamy syndrome, cleidocranial dysplasia, Basal cell nevus syndrome and may sometimes be induced by drugs such as cyclosporine and calcium blocker.[28]

Bilateral DC are rare in the absence of an underlying syndrome or systemic condition. On our data basis research (English language literature) only 22 cases of bilateral DC not related to syndromes were identified and just eight were associated to permanent mandibular right and left third molars,[23456789] females patients accounted for 37.5% of the patients. The age range for the reported cases varies from 15 to 57 years of age with 37.38 averages [Table 1]. Although, this finding may reflect the true rarity of the condition, it is conceivable that bilateral DC is either under-recognized or under-reported. In our case, there were no clinically evident syndromes.

Table 1

English based literature review of bilateral third molar dentigerous cists not related to syndromes

It is usually asymptomatic with no pain or discomfort unless it becomes secondarily infected. Therefore, DC are frequently discovered in radiographs taken to investigate a failure tooth eruption or general dental examination. Considering a normal follicular space of 3-4 mm, DC should be suspected when the space is more than 5 mm.[1] Intraoral radiography is generally performed in the routine examination; however, computed tomography-based reconstruction programs, can better determine the topography of the cystic lesion, the integrity/discontinuity of the bony margins, the proximity to vital structures and the displacement of teeth.[10] In our case, CBCT was performed to a better presurgical planning, it made possible to access and measure properly both lesions at sagittal, coronal, and axial view [Figure 1].

This condition can be associated with other concurrent pathology, such as keratocystic odontogenic tumor (KCOT), calcifying cystic odontogenic tumor and glandular odontogenic cyst, odontomas and central giant cell granulomas.[10] In our case, we report bilateral DC with no other lesion associated. There are some hypothesis that supports the notion that DC could give rise to more serious diseases such as KCOT and cystic ameloblastoma. It shows the importance of submitting samples for pathology examination even when cysts present clinically as a classical DC.[10]

Dentigerous cysts are a benign condition; however, it can cause displacement of resorption of adjacent teeth, infection and even pathologic jaw fracture. In adult patients, surgical removal of the tooth is the usual treatment for cyst-associated impacted teeth. There are some case reports of spontaneous regression if early diagnosed.[8] However, removal of associated tooth and enucleation of soft-tissue components is definitive therapy in most instances. There are two main surgical procedures to these cases, marsupialization and enucleation. In our case, marsupialization was first performed expecting new bone formation. However, no relevant new bone formation was observed 3 months later, therefore, surgical enucleation of both cysts were performed under general anesthesia together with the excision of the associated third molars. In our case, the bigger lesion had approximately 24 mm diameter and was located on the mandibular angle, this way, we found cautious to perform the plate placement fixation to avoid the possibility of trans or postoperative fracture.

Conclusions

In case of multiple DC, a trough clinical and systematic examination should be done to rule out any associated syndrome. Early detection and removal is important to reduce morbidity and avoid more aggressive surgical procedures.