Treatment of Keratocystic Odontogenic Tumours: A 10-Year Review of Cases

Previously known as the odontogenic keratocyst, the World Health Organization reclassified this lesion as the keratocystic odontogenic tumour (KCOT). Although it is a benign lesion, the designation of this lesion by the WHO as a tumour is thought to highlight the aggressive behaviour and potential neoplastic nature of this lesion. Clinically these lesions are slow growing and often remain asymptomatic until significant enlargement has occurred, and are associated with the naevoid basal cell carcinoma syndrome (Golin-Goltz). There are 3 histological variants: orthokeratinised, parakeratinised, or both, which dictate the treatment modality.

Treatment of KOTCs remains controversial, and multiple surgical management techniques have been reported including decompression, marsupialisation, enucleation with or without the use of adjuncts (Carnoy’s solution or cryotherapy), or surgical resection (marginal or segmental). Treatment must balance minimizing recurrence rate with reduction of morbidity associated with resection.

This study retrospectively reviewed the management of a cohort of cases seen over an 8-year period within a single unit in London with particular focus on the surgical treatment modalities and the relative rates of relapse. 317 cases were identified for inclusion however complete data was available for 43 cases with follow-up ranging for a period of 8 years (from 2004-2015). The results were analysed statistically and are presented here.

Data collected included demographic information, surgical method, length of clinical and radiographic follow up, and any recurrences.

The cohort showed a male to female ratio of almost 2:1. The peak incidence of KCOTs appeared to occur in the 3^rd and 5^th decades.  Administered treatment modalities included enucleation (49%), enucleation with the use of Carnoy’s solution (47%), and marsupialisation (4%). Marsupialisation was carried out to allow a partial decrease in size of the lesion and to preserve vital structures like the teeth and inferior alveolar nerve prior to enucleation with the use of Carnoy’s solution in these cases. Many cases resulted in enucleation alone due to misdiagnosis in the treatment planning often resulting in patients being treated with enucleation alone due to a working diagnosis of a dentigerous cyst, which would not warrant the use of Carnoy’s solution. IAN nerve injury occurred in 11 cases (26%) however this resolved within 6 months except in 1 case where it persisted to become a permanent nerve injury. 57% presented in the mandible. The mean clinical and radiographic follow up period was 5.4 years but this ranged from 2 to 8 years post surgery. The recurrence rate of KCOT was 16%. The majority of cases recurred after 55 months, which corresponds to that reported in the literature of 5-7 years.

The WHO reclassification as a tumor underscores the fact that this lesion should not be treated as the simple cyst it was once believed to be. Although some studies advocate a conservative approach in treating these lesions, more aggressive treatment reduces the likelihood of recurrence and therefore the risk of trauma associated with repeated surgeries. Surgical resection yields the most promising results, however this approach is fairly extreme. Therefore unless resection is deemed necessary, enucleation with the use of Carnoy’s solution appears to be the most appropriate action with good post-operative results. Long-term follow-up is required due to the likelihood of recurrence.

References:

Madras J, Lapointe H. Keratocystic odontogenic tumour: reclassification of the odontogenic keratocyst from cyst to tumour. J Can Dent Assoc. 2008;74(2):165–165h.

Johnson NR, Batstone MD, Savage NW. Management and recurrence of keratocystic odontogenic tumor: a systematic review. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013;116(4):e271–6.