Odontogenic Keratocyst in Maxillary Sinus with Ectopic Third Molar: A Case Report

Introduction

Odontogenic keratocyst (OKC) is a prevalent odontogenic cystic mass believed to originate from remnants of the dental lamina [1]. Despite its slow growth and benign nature, OKC exhibits infiltrative characteristics and a propensity for post-surgery recurrence. Most OKCs occur in the mandible, with the posterior region of the dental arch, the angle, or the ramus being the most commonly affected sites, accounting for approximately 66% to 77% of cases. In contrast, the maxilla is less frequently affected, with only about 22% of OKCs occurring in this location, and the maxillary sinus is the least common site, accounting for only about 1% of cases [2].

The maxillary sinuses, the largest and most developed sinuses, are closely associated with the maxillary third molar [3]. Impacted tooth formation frequently occurs when the maxillary third molar fails to erupt properly. During clinical extraction of the maxillary third molar, teeth may inadvertently enter the maxillary sinus [4]. However, entry of a non-iatrogenic ectopic tooth into the maxillary sinus is extremely rare. This paper presents a case study of an ectopic maxillary third molar located within the maxillary sinus, accompanied by OKC. This case underscores the importance of promptly extracting the ectopic tooth to prevent cyst formation. The presence of a cyst in the maxillary sinus should prompt consideration of odontogenic keratosis as a potential diagnosis.

Case Report

DIAGNOSIS AT A GLANCE:

Odontogenic keratocyst in the maxillary sinus with ectopic third molar.

TREATMENT:

The cyst was scraped and the tooth was removed under general anesthesia via the Caldwell-Luc approach (Figure 3). The angular flap was incised on the buccal aspect of the left maxilla to expose the bone surface, followed by the use of an ultrasonic bone knife to perform rectangular debulking of the anterior wall of the maxillary sinus. Upon opening the maxillary sinus, 28 ectopic teeth were observed adhering to the inner wall, surrounded by a thick cystic wall containing keratinized material, impacting the inferior and medial walls of the sinus. The cyst wall was meticulously dissected and 28 teeth were successfully extracted. Extended chemical cauterization was done using freshly prepared Carnoy’s solution. Oral antibiotics were administered to prevent infection. The postoperative pathological examination indicated the presence of incomplete keratosis on the surface of the capsule wall and a palisade arrangement of basal cells, findings that were in accordance with a diagnosis of odontogenic keratosis (Figure 4).

FOLLOW-UP:

After a 6-month follow-up period, there was no evidence of cyst recurrence in the patient (Figure 5). The patient provided informed consent for publication of this case report.

Discussion

The term odontogenic keratocyst (OKC), initially defined by Philisen in 1956 as an isolated cystic lesion enclosed by a thin layer of cortical bone, was reclassified by the World Health Organization (WHO) in 2005 as an odontogenic benign tumor due to its high proliferation potential, unique growth pattern, and tendency to recur following conservative treatment, hence termed “keratocystic odontogenic tumour” [1]. However, in 2017, the WHO reversed its earlier classification and continued to designate it as a cyst, retaining the designation “OKC” [2,5].

Odontogenic keratocyst accounts for 7.8% of jaw cysts, with incidence rates of 4% to 16.5%, predominantly affecting young adults. Sex differences are not prominent, with lesions commonly found in the mandibular third molar area and mandibular branch [2]. The occurrence of OKC in the maxilla is uncommon, typically found in the maxillary tubercles. The presence of OKC in the maxillary sinus, as documented in this study, is exceptionally rare, accounting for only approximately 1% of cases [6].

Clinical presentations of OKC resemble those of typical jaw cysts, with potential absence of symptoms in the early stages and later manifestations including soft-tissue or jaw swelling, tooth mobility, and displacement [7]. Unlike meloblastoma, OKC tends to grow along the jaw’s long axis, resulting in less pronounced jaw swelling. OKC in the maxillary sinus may present as headache [8], intra-oral swelling with pus discharge [6], pain and swelling in the maxillary region [6], diffuse painful [9], retro-orbital pain [7], or no clinical symptoms [10]. In the present case, the patient also had no obvious clinical symptoms, which may be due to the relatively limited lesions and no obvious jawbone invasion, and in this case the maxillary third molar was ectopic to the medial wall of the maxillary sinus, which is uncommon.

Imaging findings indicate that OKC typically manifests in the mandibular angle and maxillary third molar regions, presenting as either solitary or multiple lesions with variable extent. These cysts typically exhibit a circular or oval radiographic appearance with well-defined borders, potential cortical alterations, uniform internal density, and the possibility of either unilocular or multilocular presentation [11]. Computed tomography (CT) imaging reveals a low-density lesion with a density slightly greater than that of muscle tissue. In addition to mandibular OKC, a small proportion of OKCs occur in the surrounding soft tissues, such as the gums, buccal mucosa, and muscles [12,13]. If OKC presents with bifurcated ribs and widening of the orbital distance, a diagnosis of nevoid basal cell syndrome may be warranted [14].

The characteristic lesions of OKCs typically present as cystic structures with delicate and fragile walls. The majority of these cysts contain yellowish-white shiny keratinous or caseous materials within their capsules, with occasional instances of thin sacs containing light yellow or brown fluid. Solid lesions are infrequently observed in clinical practice [15]. Common histological characteristics of odontogenic keratocysts (OKC) include a connective tissue capsule with a multilayer squamous epithelium of uniform thickness, consisting of 5 to 8 layers of cells without epithelial spikes. The basal cell layer is well-defined, typically composed of cubic or columnar cells arranged in a palisade pattern with deeply stained nuclei and frequent nuclear division. The spinous layer is thin with subtle differentiation, while the surface keratinized layer exhibits incomplete keratinization and a wavy epithelial surface [2,15].

OKC is usually treated with enucleation and curettage. Due to its tendency to recur, the wound is usually treated with peripheral ostectomy, cryotherapy, Carnoy’s solution, or 5-fluorouracil [16]. OKC located in the maxillary sinuses can be effectively managed through endoscopic or surgical intervention utilizing the Caldwell-Luc approach. This approach allows for complete exposure of the maxillary sinuses and anterior maxillary region, facilitating thorough removal of the lesion with minimal tissue damage and expedited recovery [17]. In the present case, the Caldwell-Luc approach was employed to perform cyst curettage, resulting in a mild postoperative response devoid of evident complications. Despite the absence of recurrence within a 6-month follow-up period, the long-term implications of the observed factors related to the recurrence of OKCs warrant further observation. These factors include the posterior location of the lesion in the jaw, the multilocular nature of the imaging, penetration of the bone cortex by the lesion, and incomplete surgical intervention. Given the high-risk location of the lesion in the maxillary sinus, a more rigorous follow-up protocol is recommended.

Conclusions

Odontogenic keratocyst in the maxillary sinus can be accompanied by ectopic third molars and initially present as asymptomatic. Surgical intervention using the Caldwell-Luc approach has been shown to yield favorable outcomes.