Dentigerous cysts (DC) are the most frequent type of developmental odontogenic cyst derived from the tooth-forming organ 1–3. It most commonly occurs in the second to third decades of life 4. It originates by separation of follicle and filling with fluid from around the crown of an unerupted tooth. DC is the most common odontogenic cyst, secondary to radicular cyst. The teeth most involved are as follows in the descending order of occurrence: third molars, canines, and second premolars. It may also be associated with an impacted, supernumerary, or an ectopically erupted tooth. Most commonly observed ectopically erupting teeth are third molars.
Radiographically, DC appears as a unilocular radiolucent shadow with well-defined sclerotic border, which, when infected, will show ill-defined borders, associated with the crown of the unerupted tooth 4,5.
This article describes a case of an aggressive infected DC arising from an ectopically erupted left maxillary third molar in the maxillary sinus in a 15-year-old female patient, mimicking a potentially aggressive lesion extending into the ethmoidal and frontal sinus.
A 15-year-old female patient reported to our Department of Oral and Maxillofacial Surgery, KMCT Dental College and Hospitals, with a chief complaint of foul-smelling discharge from behind the left last tooth since 1 year, with a slow-growing swelling over the left cheek. The patient had consulted specialists, with the chief complaint of chronic rhinitis, intraoral discharge, and headache 1 year back. The patient was diagnosed with chronic sinusitis and was given repeated antibiotics for the past 1 year. Despite being treated with antibiotics, the discharge persisted and the swelling slowly increased in size, without any pain. There was also a history of occasional discharge from the left nostril.
On clinical examination, the maxillary left third molar was absent. No tenderness was elicited over the left maxillary sinus. The left submandibular nodes were palpable and tender. Intraorally, the mucobuccal fold was obliterated in the region from the distal aspect of the 25 and extending posteriorly by a soft, fluctuant, nontender swelling (Fig. 1). Pus discharge was noted distal to 27 arising from the gingival margin.
A panoramic radiograph was advised, which revealed the presence of an ectopically erupted tooth 1.5 cm above the root of the 27, with the tooth in the middle third of the left maxillary sinus, which appeared hazy. Aspiration was performed and serous purulent fluid was obtained, confirming the provisional diagnosis of infected cyst.
Because of the inconclusiveness from orthopantamogram about the extent, a computed tomography (CT) was advised in the sagittal and coronal sections at the level of the maxillary sinus. It revealed a soft expansile, soft tissue dense lesion measuring 5×4×3.6 cm, with a thin bone rim occupying the whole of the left maxillary sinus, with a tooth visible within the lesion in its anterior aspect. The posterior and inferior margins of the lesion showed bone erosion, and the margins were well-defined without infiltration. This was indicative of an infected DC in the maxillary sinus (Figs 2 and 3). Mucosal thickening was also noted in the left frontal and ethmoidal sinuses. The lesion was extending until the ethmoidal and frontal sinuses and was eroding the lateral wall of the nose.
The patient was subjected to surgical enucleation of the cyst under general anesthesia, and empirical antibiotic therapy was started. A transvestibular incision was made extending from the distal aspect of the second molar, and a releasing incision was made between the lateral and central incisor. A bony window was created (Fig. 4) and the tooth, including the whole of the lesion, was removed in toto (Fig. 5). Peripheral ostectomy was performed when possible. The cavity created was irrigated well, and a gauze pack was placed, which was removed on the third postoperative day. Closure was performed using 4-0 vicryl, continuous interlocking sutures. The resected section was sent for histopathological studies. After the surgery, the patient was also prescribed nasal drops and steam inhalation. The patient was discharged on the fifth postoperative day with oral antibiotics.
The patient was recalled and reviewed after 1 week and during the second week. She was relatively free of her symptoms. The extraoral swelling reduced in the second postoperative week and the patient was free of the chief complaints. She was reviewed again after first and second month, and no specific complaints and intraoral incision healing that was uneventful was reported.
Histopathology of the specimen revealed a cystic lining, lined by flattened cells of stratified squamous epithelium and at places covered by granulation tissue and infiltration by mononuclear cells, suggestive of infected DC.
Ectopic eruption of a tooth into the dental environment is a relatively common occurrence, whereas ectopic eruption of a tooth in other sites is rare 6. However, there have been few reports of tooth being erupted in the nose, condyles 3, coronoid process, and maxillary sinus. DC is the most common of all developmental cysts, more common in the male population, occurring in the second and third decades of life. About 70% of DC occurs in the mandible and 30% in the maxilla 4,7,8. Teeth most commonly associated with DC are mandibular third molar 4, maxillary third molar, maxillary canines, mandibular premolar, and rarely maxillary third molar. DC is often asymptomatic, but can enlarge and cause symptoms related to expansion and impingement on contiguous structures. Patients with DC involving the maxillary sinus might present with sinusitis, proptosis, diplopia, ptosis, and epiphora, but it rarely affects visual acuity. Fracture of the orbital bone has been reported 9.
Most of the DCs are discovered accidentally on routine radiographic examination. However, radiographically, it is difficult to distinguish DCs from other jaw cysts, as most of them present as well-circumscribed radiolucent lesions. Routine CT imaging is debatable; however, it is better reserved for large lesions, especially those involving the maxilla, in which case, nasal cavity, orbital, or pterygomaxillary space extension may occur 10.
Differential diagnosis includes odontogenic keratocyst, adenomatoid odontogenic tumor, calcifying epithelial odontogenic cyst, calcifying epithelial odontogenic tumour, and unicystic ameloblastoma. In addition to the histopathological and radiological alteration, researchers recently proved that the biochemical markers such as BMP-4 11 and immunohistochemical markers such as Bcl-2 and Bcl-xL can be used for differentiation of DC from odontogenic keratocyst and unicystic ameloblastomas 10. Finally, because of diverse disease entities, expansile lesions of the maxilla includes malignant tumors and benign conditions, including fibro-osseous diseases and mucoceles. The exact site of origin is very important for differential diagnosis, as a lesion of the antral region is likely to be a maxillary mucocele; for extra-antral maxillary cystic lesion, the probable diagnoses are fissural cysts, cystic tumors of maxilla, or cystic masses of dental origin 11.
Since its introduction, the Caldwell–Luc procedure has become a standard approach for the management of antral disease, as well as an operative route to reach such sites as the pterygomaxillary space, orbit ethmoid labyrinth, and medial skull base. The advancement in endoscopic sinus surgery, however, has changed many indications for Caldwell–Luc procedure. However, in such conditions in which an aggressive, suppurative, lesion with a tooth is within the maxillary sinus, Caldwell–Luc procedure itself might prove beneficial.
Diverse disease entities may cause malignant and benign expansile masses in the maxilla. The CT may be helpful in defining the extent, especially in lesions with larger dimensions. Infected DC may show features of malignant tumors. The standard treatment for DC is enucleation and removal of the involved teeth. Marsupialization is suggested in the pediatric group, and thus was not attempted in this patient. If left untreated, other than the usual complications, it can undergo carcinomatous transformation such as epidermoid carcinoma.
Conflicts of interest
There are no conflicts of interest.
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