Swelling in the maxillary region, especially unilateral, is a surgical enigma. The condition is very rare but misleading as a variety of conditions can mimic it. They may be anything from an ossifying fibroma to a developmental odontogenic cyst. These developmental cysts are generally found by chance after a routine X-ray, unless big enough to cause symptoms, and are rarely related to supernumerary teeth [1,2]. They are most commonly identified associated with mandibular third molars and maxillary canines. These cysts normally appear in young adults, between 20 and 30 years of age [3]. Hence unilateral maxillary swellings warrant a detailed history and appropriate investigations to narrow down to a diagnosis and then further management must be done according to the type of lesion.

A 27-year-old female came to our outpatient department with swelling in the left nasolabial - maxillary region for the past 9 months. The swelling was initially like a peanut and gradually increased in size. It was initially associated with pain, which was compressive in nature, aggravated by brushing/chewing, which gradually diminished and stopped. There was a history of assault by the husband to the left side of the face 2 years back.

Clinical examination revealed a mild elevation of the floor of the left nasal cavity along with facial asymmetry caused by swelling of the left maxillary region. The swelling was firm with eggshell crackling sensation, tender, not resonant, covered with normal skin, extending from the left nasolabial fold, abutting the floor of the left nasal cavity, to the zygoma laterally, the inferior orbital ridge of the orbit superiorly and pyriform aperture inferiorly. Intraoral examination revealed a hard swelling in the alveolus obliterating the gingivobuccal sulcus extending from the right upper central incisor to the upper left second premolar. There were no loose teeth. A provisional diagnosis of a nasolabial cyst was made.

Computed Tomography (CT) of the face was taken, which showed evidence of a cystic lesion of size approximately 3x3x2.6 cm arising from the apices of upper right medial incisor to upper left first premolar extending till inferior orbital ridge superiorly, nasal bone and inferior turbinate

After obtaining pre-anesthetic clearance, the patient was taken up for cyst excision under general anesthesia. The buccal vestibular incision was made in the upper jaw with two vertical releasing incisions and mucoperiosteal flap elevated. The cyst was enucleated completely and sent for histopathological examination (HPE).

Extraction of the left upper lateral incisor along with apicectomy of the right upper medial incisor till the left upper first premolar was performed. Caldwell – Luc procedure was done as the cyst involved nasal floor. The repair of the left nasal cavity floor was done with 5-0 vicryl. Platelet-rich- Fibrin (PRF) was placed on the enucleated socket to accelerate the healing of soft and hard tissues. The flap was closed with 3-0 vicryl. The patient recovered well postoperatively. HPE came back as a dentigerous cyst.

The differential diagnosis for a maxillary swelling should be achieved based on the anatomical structures present in that location. Some of these structures may be developmental in origin or due to trauma or infection. As the most common type of developmental odontogenic cyst, the dentigerous cyst is defined as an odontogenic cyst derived from reduced enamel epithelium surrounding the crown of an unerupted tooth [4]. It is commonly associated with unerupted mandibular or maxillary third molars or maxillary cuspids. It occurs at any age but has a peak incidence in patients from the 10-30 years age group [5,6]. Whereas it was associated with premolars in our case which was an abnormal presentation.

Dentigerous cysts are the second most common odontogenic cysts appearing in the jaws, after radicular cysts [7,8]. When the maxillary sinus/bone is invaded, symptoms usually occur late in the process; the cyst usually remains asymptomatic but may produce painless bony expansion or facial asymmetry if it becomes large [9,10]. The patient presented to us without any major complaints suggesting that there was no underlying active inflammation or infection. Since a number of conditions can present with facial swelling the following differential diagnosis was thought of - fibrous dysplasia, odontogenic keratocyst, nasolabial cyst, and even periapical cyst.

The above conditions were ruled out based on socio-demographic and clinic radiological data.