Optimizing Treatment Outcomes for Odontogenic Keratocyst

ABSTRACT

The treatment of odontogenic keratocysts (OKCs) continues to be a contentious issue in oral and maxillofacial surgery. Despite extensive research and systematic reviews, no definitive protocol or consensus has been established. This case series investigates how OKCs can be treated through a thorough approach combining preoperative investigation – fine needle aspiration cytology (FNAC) – to confirm the diagnosis of OKC, followed by treatment of the combined surgical approach of enucleation, peripheral ostectomy, and chemical cauterization using modified Carnoy’s solution under local or general anesthesia. This study demonstrates how well this multimodal therapy method works in lowering the chances of recurrence and reaching the best results.

INTRODUCTION

Odontogenic keratocysts (OKCs) were first identified by Philipsen in 1956, originally categorized as a developmental odontogenic cyst by the WHO (World Health Organization); its features were outlined by Pindborg and Hansen. In 2005, it was classified as KCOT (keratocystic odontogenic tumor) because of its aggressive behavior and frequent reappearance. However, WHO changed OKC back to being classified as a cyst in 2017. OKC originates from leftover tissue of the dental lamina and is identified by a layer of stratified squamous epithelium that creates keratin.[1,2]

OKC is often seen in the mandible with the highest occurrence in people in their 20s and 40s. The cyst usually grows slowly inside the bone’s medullary space. Radiographically, OKCs are seen as unilocular or multilocular, showing scalloped margins, often linked to impacted teeth. Expansion of bone and resorption of neighboring teeth roots could also be seen.[3] The diagnosis of OKC is based on clinical, radiographic, and histopathological findings. Although radiographic features help with initial identification, the definitive diagnosis is established by examining the histology, which reveals a wrinkled epithelial lining with para- or orthokeratinization, with four to six layers, as well as daughter cells. Advanced diagnostic procedures can include immunohistochemical examination of Ki-67 and Bcl-2, along with next-generation sequencing for the PTCH1 gene.[4] The basal and suprabasal layers contain Bcl-2, cytokeratin 10, and interleukins, which suppress the apoptosis of the surface epithelium, contributing to the high recurrence rate. A variety of treatment methods have been employed to manage OKC, including both conservative and aggressive approaches. These range from enucleation with or without curettage, marsupialization, peripheral ostectomy, chemical cauterization, and resection. Goyal et al.[5] studied 42 cases to assess the role of fine needle aspiration cytology (FNAC) in diagnosing intraosseous jaw lesions, reporting a sensitivity of 94.7%, a specificity of 100%, and a diagnostic accuracy of 97.3%. Hence, FNAC can be used as an important preoperative diagnostic tool which is quick and safe aid in early management.

We followed our center’s protocol for OKC cases, with four of these cases presented in this article. The diagnosis was validated by FNAC without any incisional biopsy. Following that, enucleation of the lesions, peripheral ostectomy, and cauterization with modified Carnoy’s solution were done.

CASE PRESENTATION

This report presents three cases of odontogenic keratocyst and one case of OOC (orthokeratinized odontogenic cyst), all characterized by extensive lesions resulting from anterior–posterior expansion, which were managed conservatively.

Case 1

A 42-year-old woman presented with a 2-month history of swelling in the right lower back teeth region. Clinical examination revealed asymmetrical swelling over the right mandible of size 3*3 cm extending from 44 to 47, with hard consistency, bony tenderness, and mild buccal and lingual expansion. OPG and CBCT revealed a well-defined, unilocular lesion with a scalloped border of size 4*4 cm in the periapical region of 44-48.

Case 2

A 35-year-old woman arrived with a 2-month history of pain in the lower front teeth region. Intraoral examination revealed a 3 × 3 cm swelling extending from 33 to 46. Signs of inflammation were evident. Preoperative CBCT reveals well-defined radiolucent lesions of size 4*3 cm with a scalloped margin and root resorption of 42 and 43 [Figure 1].

Figure 1.

OPG of case 1 reveals well-defined, unilocular lesion with a scalloped border of size 4*3 cm in the periapical region of 44-48

Case 3

An 18-year-old female showed up with a swelling in the left lower back teeth region with 1 month duration. During the clinical examination, no signs of infection or inflammation were found. During the intraoral examination, a 2 × 3 cm swelling was found from the distal aspect 37 to the left ramus region. Preoperative CBCT revealed a well-defined radiolucency of size 6*3 cm extending from the periapical region of 36, 37 till the subcondyle and coronoid region with scalloped borders. Impacted 38 was evident in the lower border of mandible [Figure 2].

Figure 2.

CBCT of case 3 reveals a radiolucency of size 6*3 cm with impacted 48

Case 4

A 39-year-old male patient sought to replace his missing teeth. He had a history of OKC enucleation in the right mandible 5 years prior. An incidental finding on an OPG showed a 3 × 3 cm radiolucent area in the left posterior mandible and a 3 × 2 cm radiolucent area in the anterior maxilla. Clinical assessment revealed no signs of infection, swelling, or syndromic features. CBCT showed a well-defined hypodense lesion from the mandibular ramus to the periapical region of 37 and another in the periapical region of 11, 12, and 21, with impacted 13.

Treatment protocol

Preoperative FNAC was performed on all patients as the primary diagnostic tool, revealing a creamy white material. In cases 1, 3, and 4, surgical enucleation with peripheral ostectomy and modified Carnoy’s cauterization (under 3 minutes) was done under general anesthesia. In case 2, the same procedure was carried out under local anesthesia due to the lesion’s easy accessibility in the anterior mandible [Figure 3]. Histopathological examination confirmed OKC [Figure 4] for cases 1, 2, and 3 and OOC for case 4. Two years follow-up has been conducted so far for all the patients, and postoperative OPG and CBCT revealed no recurrence and the bone regeneration was satisfactory [Figures 5 and 6].

Figure 3.

Surgical protocol: a. cyst enucleation, b. peripheral ostectomy, c. cornoy's application, d. closure

Figure 4.

Histopathology picture of OKC

Figure 5.

Post operative OPG of case 2

Figure 6.

Post operative OPG of case 3

DISCUSSION

The classification of OKCs has changed throughout time to reflect their unique biological traits and the need for a diversified treatment strategy. The 2022 WHO classification of head and neck tumors recognized OOC as a distinct entity, with multiple OOCs being particularly rare.[4] Case 4 in this study exemplifies this uncommon occurrence.

Surgical enucleation was initially described by Thoma and Goldman (1946) as a treatment for odontogenic tumours.[1] Adjunctive procedures have been developed to enhance treatment outcomes and address the recurrence of OKCs. Surgical enucleation with adjunctive procedures was evidenced by the studies of Al-Moraissi et al. (2023) and Titinchi (2020), who showed success in decreasing the chances of recurrence and managing the aggressive behavior of OKCs.[6,7] Karaca et al.[8] reported 14.8% recurrence rate was observed in enucleation and peripheral ostectomy. Carnoy’s solution has been a useful adjuvant therapy for the treatment of OKC. Najwa in 2017 reported 0% recurrence in his 29 cases and stated that enucleation followed by peripheral ostectomy and chemical cauterization with Carnoy’s solution is the standardized treatment for OKC.[9] Using Carnoy’s solution following enucleation greatly decreases the recurrence rate, with rates as low as 1.6%.[10]

These studies highlight the significance of customized treatment planning based on lesion characteristics and patient-specific parameters. Reports on the use of FNAC in diagnosing OKCs are rare. Vargas et al.[11] in their study of eight patients of OKC used FNAC as a preoperative diagnostic tool. Sunita Singh et al.[12] studied the role of FNAC in oral lesions and found 77.7% sensitivity and 100% specificity. False positive results with FNAC were rare. The primary treatment method in this study was surgical enucleation followed by peripheral ostectomy and chemical cauterization with modified Carnoy’s solution, when FNAC revealed a creamy white material. Further preoperative incisional biopsy was not done in these cases considering the fact that that will increase the rate of infection and prolongs the definitive treatment. Although more research is required to investigate the long-term effectiveness and safety, the method outlined in this study shows potential as a successful approach for treating OKCs and enhancing patient results.

CONCLUSION

Utilizing FNAC as a preoperative diagnostic tool, combined with surgery and chemical cauterization using modified Carnoy’s solution, provides a comprehensive approach for treating OKCs. This method aims to fully remove the cyst lining and reduce the risk of recurrence. This approach has demonstrated notable benefits, such as decreased rates of recurrence and personalized care based on individual symptoms. Advances in radiology, such as CT, MRI, and CBCT, have enhanced early detection of recurrences, allowing for more conservative management and reducing the need for radical treatments. Patients should be monitored closely with yearly OPG and MRI to detect early recurrences. Future studies should focus on the long-term effectiveness and safety of adjunctive treatments and minimally invasive methods for improving OKC management.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.