Keywords
dentigerous cyst - enucleation - maxilla - radiolucent - squamous epithelium - unerupted
tooth
Introduction
Dentigerous cysts are cystic lesions in the oral and maxillofacial area radiographically
represented by a well-defined unilocular radiolucent area usually involving an impacted
tooth crown. It is considered as the most common type of odontogenic cyst at approximately
20% of all jaw cysts. It is mainly associated with the mandibular third molar, maxillary
third molar and maxillary canines, with peak incidence in the second and third decades.[1] The occurrence of this cyst in the first decade is relatively low at approximately
4 to 7%. Histologically, they are represented by a cavity lined by the nonkeratinizing
thin epithelium without rete pegs.[2] These cysts are usually asymptomatic and are detected by routine radiographic examination.
The removal of the cystic lesion and the extraction of the unerupted tooth is the
main treatment to prevent the recurrence of the cystic lesion.[3] This case report presents a case of dentigerous cyst in the right maxillary region
in a young child and was diagnosed using radiographs and removed by surgical excision.
Case Report
A 7-year-old male reported to the department of oral medicine and radiology with the
chief complaint of swelling in the upper right front region of the jaw and delayed
eruption of upper front tooth for the past 2 months but not associated with pain.
History revealed that the swelling was insidious in onset, which gradually increased
and attained the present size. There was no history of fever, trauma, bleeding or
pus discharge related with the swelling. The past medical and family history was not
contributory.
On general examination, the patient appeared moderately built and nourished. On extraoral
examination mild facial asymmetry in the right maxillary region was observed. On palpation,
the swelling was firm to hard in consistency, nontender, fixed to the underlying bone,
free from the overlying skin, and with no tenderness or secondary changes. Intraorally,
a solitary swelling was present in the right maxillary labial gingival and labial
vestibular region, measuring approximately 2.0 × 2.0 cm, extending superiorly from
the labial vestibular region and inferiorly to the marginal gingival region in relation
to the right maxillary central incisor (11) and lateral incisor (12). The swelling
appears to extend till the palatal gingival region in the right maxillary incisors.
The surface of the lesion appeared smooth with diffuse borders and no secondary changes
like bleeding or pus discharge present ([Fig. 1A], [B]). On palpation, swelling was nontender, noncompressible, nonpulsatile, not depressible,
and hard in consistency with expansion of labial and palatal cortical regions.
Fig. 1 Intraoral preoperative photograph of the lesion (A, B). Preoperative maxillary occlusal radiograph (C) and orthopantomogram (D). White arrows indicate the lesion.
The patient’s consent was obtained and the radiographical examination was performed.
Radiological examination was performed using maxillary occlusal radiograph, and orthopantomogram
revealed a well-defined radiolucent area approximately 2.0 × 2.0 cm with well-defined
radiopaque borders in the posterior region in relation to 11, 12, 13, 14, 52 and 53.
There was displacement of permanent and deciduous right maxillary incisors (11,12,
13, 52 and 53) and the radiolucency was laterally along the tooth root, partially
surrounding the crown suggestive of the lateral variety. There was no root resorption
and the surrounding bone appeared normal. Orthopantomogram reveals erupting permanent
premolars, first molars, second molars, and developing third molars. The biochemical
and microbiological investigations were within normal limits ([Fig. 1C]
[D]).
Complete surgical excision of the lesion was done under local anesthesia. Teeth (52,
53 and 11) were extracted as on surgical exposure, the roots were completely contained
in the lesion ([Fig. 2A]). The permanent maxillary incisor was extracted, as the tooth was completely contained
inside the lesion. Gross examination of the specimen showed gray white cystic soft-tissue
fragments ([Fig. 2C]). Histopathological examination revealed lesion lined by stratified squamous epithelium
with ulceration, and stroma showed collections of inflammatory infiltrate composed
of lymphocytes and plasma cells, congested by blood vessels with focal myxoid change
and hemorrhage. Bony spicules were seen ([Fig. 2B]).
Fig. 2 Intraoperative photograph of the lesion (A) and the excised lesion along with the extracted teeth (B). Photograph of histopathological section, revealing lesion lined by stratified squamous
epithelium with ulceration, and stroma showing collections of inflammatory infiltrate
composed of lymphocytes and plasma cells, congested by blood vessels with focal myxoid
change and areas of hemorrhage (C).
The overall clinical, radiologic and histopathological diagnosis confirmed the final
diagnosis of dentigerous cyst. The follow-up occlusal radiograph was taken by the
second month, which showed no recurrence of the lesion at the site ([Fig. 3C]) The patient is under regular follow-up for the past 1 year, the eruption pattern
of other teeth appears normal, and the rehabilitation will be done when the adjacent
permanent teeth erupt and bone growth is adequate ([Fig. 3A]
[B]).
Fig. 3 Immediate postoperative photograph of the lesion (A) 3-month follow-up photograph (B). 3-month postoperative maxillary occlusal radiograph (C).
Discussion
Dentigerous cyst is a type of odontogenic cyst that encloses the crown of an unerupted
tooth by expansion of the follicle and is commonly attached to the neck of the involved
tooth. The term dentigerous is preferred, the literal meaning being “tooth bearing.”[4] Dentigerous cysts are usually asymptomatic, with the majority of small cysts identified
incidentally through routine radiographic examination or occasionally from delay in
the eruption of a permanent tooth.[5] The average age of children who develop the dentigerous cysts is 11.05 years. This
is the age in which the permanent canines and premolars have their greatest eruptive
potential and the widening of dental follicle is a part of the eruptive process.[6] Dentigerous cysts in the pediatric group commonly occur in the late mixed dentition
period, as there is increased probability of impaction of the maxillary canines and
of periapical inflammation from a nonvital deciduous tooth spreading to involve the
follicle of an unerupted permanent succedaneous tooth.
Two types of dentigerous cysts have been described according to the etiopathogenesis.
-
Developmental and inflammatory types. The developmental type is the most common type,
which usually surrounds the crown of an unerupted tooth by fluid accumulation between
the layers of the enamel organ.[7] The inflammatory type of dentigerous cyst is usually associated with the roots of
a nonvital primary tooth.[8] Three types of dentigerous cyst have been radiographically described by Thoma-Robinson-Bernier:
The central variety, in which the radiolucency surrounds just the crown of the tooth,
with the crown projecting into the cyst lumen. In the lateral variety, the cyst develops
laterally along the tooth root and partially surrounds the crown, and the circumferential
variant exists where the cyst surrounds the crown and extends down along the root[9] ([Fig. 4A]
[B]
[C]).
Fig. 4 The central variety, in which the radiolucency surrounds just the crown of the tooth,
with the crown projecting into the cyst lumen (A). In the lateral variety, the cyst develops laterally along the tooth root and partially
surrounds the crown, (B) and the circumferential variant exists where the cyst surrounds the crown and extends
down along the root (C).
It is commonly associated with impacted, unerupted, embedded tooth, odontome or supernumerary
tooth. Large odontoma can cause a delay in the eruption of permanent teeth and can
further develop cystic lesions as dentigerous cysts.[10] The clinical examination reveals a missing tooth or teeth and possibly a hard swelling,
occasionally resulting in facial asymmetry with no pain or discomfort.[11] Delayed tooth eruption of the involved tooth is also a common presentation. Bilateral
and multiple cysts have been reported in patients with syndromes such as basal cell
nevus syndrome, mucopolysaccharidosis, cleidocranial dysplasia, and prolonged concurrent
use of cyclosporine and calcium channel blockers.[12]
[13] The dentigerous cyst is potentially capable of becoming an aggressive lesion. Expansion
of the bone with facial asymmetry, displacement of teeth, severe root resorption of
the adjacent teeth, and pain are possible sequelae brought about by continued enlargement
of the cyst.[14] Cystic involvement of the unerupted mandibular third molar usually results in a
“hollowing-out” of the ramus, extending up to coronoid process and condylar process,
and expansion of the cortical plate due to the pressure exerted by the lesion.[14]
Radiographically, the cyst presents as a well-defined unilocular radiolucency, often
with sclerotic border. Since the epithelial lining is derived from the reduced enamel
epithelium, this radiolucency typically surrounds the crown of the tooth.[9] If the follicular space on radiograph is more than 5 mm, an odontogenic cyst can
be suspected. Other odontogenic cysts like radicular cysts, odontogenic keratocysts,
and odontogenic tumors such as ameloblastoma, Pindborg tumor, odontoma, odontogenic
fibroma, and cementomas may share the same radiologic features as dentigerous cysts.[12] A large dentigerous cyst may be multilocular in radiological appearance because
of the persistence of bone trabeculae within the radiolucent area.
The dentigerous cyst is normally lined with nonkeratinized stratified squamous epithelium
and filled with clear, amber-colored fluid that not infrequently is rich in cholesterol
and cholesterol esters.[15] Rete peg formation is usually absent except in cases which are secondarily infected.
The connective tissue wall is thickened and composed of a loose fibrous connective
tissue or sparsely collagenized myxomatous tissue.[14] As the lining is derived from reduced enamel epithelium, it is generally 2 to 4
cell layer thick primitive type.[9] The impacted tooth exerts a pressure on follicle, which obstructs the venous outflow
and induces a rapid transudation of serum across capillary walls. The increased hydrostatic
pressure exerted by pooling of this fluid causes separation of crown from follicle
with or without the reduced enamel epithelium. The osmolality of the cystic fluid
is modified by the increased permeability to glycosaminoglycans like hyaluronic acid,
heparin and chondroitin sulfate, which cause expansile growth rapidly.[16]
The treatment modality is indicated in each individual case, such as cyst size and
site, patient age, the dentition involved, and the involvement of vital structures.
Cyst enucleation without extraction of the impaction, and decompression are two treatment
modalities indicated in growing children and adolescents to salvage the involved dentition.[17] In extensive lesion, surgery or marsupialization is commonly recommended for dentigerous
cysts, because they often block eruption of teeth, become large, displace teeth, destroy
bone, encroach on vital structures and, occasionally even, lead to pathologic fracture.[18] Rarely, dentigerous cyst transforms to oral squamous cell carcinoma, ameloblastoma
or mucoepidermoid carcinoma in the adult population if the cyst in untreated for a
longer period of time.
Conclusion
Dentigerous cyst is the second common odontogenic cyst in the oral and maxillofacial
region. The prognosis of the cyst is good, and recurrence is rare with regular follow-up.
Although these cysts are rare in the first decade, they can develop in the early stages
of life, and cause interference in tooth development and eruption pattern. Hence,
early clinical, histopathological diagnosis and complete excision of the lesion with
long-term follow-up is required to prevent occurrence of destructive lesions.
