Endoscopic management of a giant dentigerous cyst

Abstract

Dentigerous cyst is one of the most common developmental cyst of the jaw which accounts for approximately 20%–30% of bone cyst in the head and neck region. Most common site is the third molar of the mandible. However, maxillary involvement is not uncommon. The clinical presentation of this depends mainly on the size and anatomical compromise that occur due to compression. This case highlights the role of endoscopic approach in the management of large expansible cyst of maxilla involving the palate, thus preserving the anatomy and reducing the morbidity associated with an open procedure.

Background

Dentigerous cyst is a slowly expansible bone cyst also known as follicular cyst, that is derived from the epithelial lining of the tooth forming organ. Due to its slow expansible nature, the peak incidence and clinical presentation of this lesion are generally noted in second and third decades of life.¹ Dentigerous cyst accounts for approximately 20%–30% of all the true cysts found in the jaw.² Most frequently, lower third molar is involved by this lesion. Bilateral cysts usually are rare and occur with syndromic or systemic diseases.³

Dentigerous cysts are considered due to cystic changes that occur in the remnants of an unformed enamel organ that includes the crown of an unerrupted tooth that is attached to the cemento enamel junction.⁴

The slowly expansible nature of the cyst is mainly due to collection of fluid in the space between the reduced enamel epithelium surrounding the unerupted tooth. During the process, the accumulated fluid compresses the tooth follicle. This obstructs venous outflow and induces transduction of serum through the capillaries.⁵

Case presentation

A 31-year-old man presented to the out patient department with problems of painless gradually progressive swelling over the hard palate for 7 years, and nasal block on and off for 4 years. He had a history of snoring and mouth breathing. There was no history of trauma or epistaxis, and it was not associated with any pain; it was associated with local discomfort. The swelling had been slowly increasing in size since it was first noticed. The patient is a known case of systemic hypertension, and on regular medication. There was no relevant dental or significant family history.

Intraoral examination revealed a solitary swelling of size approximately 5*5 cm found in the centre of palate, which was pink in colour (covered with normal mucosa) with bluish hue and margins were well defined (figure 1). On palpation, swelling was soft to firm in consistency, immobile, non-tender and covered by palatal mucosa. Swelling was also noted in the right nasal cavity and causing a bulge in the right nasal cavity, compromising the airway and pushing the septum to the left (figure 2). Eye movements were full and pain free.

Figure 1.

Intraoral clinical photograph of the oral cavity shows a solitary swelling seen in the centre of hard palate.

Figure 2.

Diagnostic nasal endoscopy shows smooth pink mass in the right nasal cavity pushing the septum to opposite side.

Investigations

Fine needle aspiration cytology

Fine needle aspiration cytology was done which showed an occasional foamy macrophage with eosinophilic proteinaceous material and cholesterol crystals, and no malignant cells were seen. The features were suggestive of a cystic lesion—inclusion cyst.

CT of nose and paranasal sinus

CT of nose and paranasal sinus showed an approximately 5*6*6 cm well-defined hypodense lesion, with incomplete peripheral hyper dense rim completely filling right maxillary sinus, eroding the medial wall and extending into nasal cavity. Minimal extension noted anterolaterally with a questionable erosion of the wall. On close examination, a thin rim of cyst wall could be identified adjacent the lateral maxillary wall. Lesion was invading the floor of right maxillary sinus, hard palate and extending inferiorly into oral cavity. Anteriorly, it was extending up to alveolar process. Lesion was seen causing deviation of nasal septum towards left side. Lesion was extending posteriorly along the nasal cavity. Cribriform plate, optic nerve and lamina papyracea appear to be normal. Possible diagnosis of mucocele/dentigerous cyst was considered (figure 3).

Figure 3.

CT of nose and paranasal sinus axial and coronal section shows hypodense lesion completely filling right maxillary sinus and extending to the nasal cavities and causing considerable bony erosions.

Differential diagnosis

Clinically, in view of hard, non-tender, non-compressible, fluctuant swelling in right side of maxilla obliterating right nasal cavity, a provisional diagnosis of dentigerous cyst, mucocele of maxilla was considered.

Radiologically, differential diagnosis of keratocystic odontogenic tumour, dentigerous cyst, mucocele, inverted papilloma with secondary mucocele, ameloblastoma were considered.

In the present case, diagnosis was confirmed through histopathological examination because the clinical and radiographic features resembled with other odontogenic lesions.

Treatment

An endoscopic excision was done under general anaesthesia, the cyst was incised on the most dependant area, and secretions suctioned out and sent for culture and sensitivity (figure 4). With the help of a 0° endoscope, the cyst wall was removed in toto from the palate, right maxilla and the nasal cavity (figure 5). Right inferior turbinectomy was performed. Specimen was sent for histopathological examination. Palatal prosthesis was placed at the site of the defect.

Figure 4.

Intraoperative photograph shows the cyst was incised.

Figure 5.

Intraoperative photograph shows the complete removal of cyst.

Histopathological examination revealed a cyst lined by non-keratinised stratified squamous enamel epithelium (figure 6). Thus, the diagnosis of dentigerous cyst was made.

Figure 6.

HPE shows a cyst lined by non-keratinised stratified squamous enamel epithelium.

Outcome and follow-up

Ryle’s tube feeds were started on first postoperative day and obturator was fixed by the periodontist. On second postoperative day, nasal pack was removed. No active anterior or posterior nasal bleed noted. On fifth postoperative day, trial oral feeds were started and Ryle’s tube was removed subsequently. Patient is on regular follow-up for the last 6 months and no features of recurrence or residue was noted (figure 7).

Figure 7.

Postoperative photograph shows the completeness of removal.

Discussion

Dentegerous cysts are benign, slow growing cysts created when fluid builds up inside the developmental sac, or follicle, surrounding an unerupted tooth. Most commonly seen in second or third decades of life.^{1 3 5} The mandibular third molar tooth is most commonly found in major cases.

Dentigerous cyst is usually located in anterior maxilla or palate, leading to a swelling in the mid-palatal region and extending to the maxillary antrum and nasal cavity. Hence, it should be carefully differentiated from other mid-palatal swellings.

Dental follicle may expand around the impacted tooth in three variations—circumferential, lateral, coronal/central.⁶

Dentigerous cyst sometimes may displace and obliterate the maxillary antrum and nasal cavities. Dentigerous cyst can be treated surgically by enucleation and or marsupialisation or enucleation with curettage.⁷

The bone eroding property in dentigerous cyst is mainly because of the multipotential nature of the cystic epithelium derived from the dental lamina. Dentigerous cyst may cause displacement of adjacent teeth and resorption of teeth roots as described in Awang and Siar.⁸ In the present case, resorption of roots or displacement of the deciduous maxillary tooth was not there.

Radiography shows well-defined radiolucent areas with unilocular or multilocular radiolucency encircling the crown of unerupted tooth; Motamedi and Talesh⁹ reported that 93% of the cyst were unilocular had smooth borders.

It can displace or obliterate the maxillary sinus and nasal cavity as seen in this case. Dentigerous cyst can sometimes progress to more aggressive lesions such as ameloblastoma, mucodermoid carcinoma and squamous cell carcinoma. CT imaging gives information about origin, size, content, expansion in relationship of the lesion to adjacent anatomical structures as described by Deana and Alves¹⁰

Reyes et al described the surgical treatment according to the case. Many authors suggested enucleation as the line of treatment and for the larger lesions may require surgical drainage and marsupialisation Cakarer et al.¹¹

The case presented here is considered to be rare due to unusual location, unusual presentation and rare management.

Patient’s perspective.

I am happy at the final outcome of treatment. I was having nasal block and snoring. The doctors examined and told me that I have a mass in my hard palate with extension into right nose and sinus causing all my symptoms. I was completely relieved of the symptoms following surgery within a week and I am happy to share my findings which might be useful in medical sciences and improving the patient care.

Learning points.

• A giant dentigerous cyst can present as either mid-palatal swelling and or as nasal swelling.

• An endoscopic approach was used to successfully excise the lesion in toto with no evidence of recurrence or residue without any complication.

• Dentigerous cyst presenting as a mid-palatal swelling is rare and may arise from the impacted super numerary tooth. It also should be considered as a differential diagnosis of mid-palatine and or nasal swelling and treatment depends on the age, size, location and the position of the involved tooth.