Odontogenic keratocysts study in Finland

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Odontogenic keratocysts going undiagnosed for too long, study finds

A large sample size has yielded some striking results in a Finnish study on OKCs. (Image: Suttha Burawonk/Shutterstock)

TURKU, Finland: Purportedly arising from remnants of the dental lamina, odontogenic keratocysts (OKCs) make up roughly 5%–15% of all odontogenic cysts and appear as either a solitary lesion or multiple lesions. They typically grow rapidly and have high rates of recurrence. Research conducted at the University of Turku on a Finnish population has found that patients with OKCs tended to be older at the time of diagnosis and their cysts were more commonly inflamed than has been reported in the literature. The findings suggest a delay in diagnosis, as OKCs are often asymptomatic and can go undetected until symptoms like swelling or infection manifest.

The retrospective study reviewed data on 174 patients diagnosed with OKCs between 1980 and 2016, aiming to evaluate the histopathological features, incidence and recurrence of OKCs in south-western Finland, an area representing 9% of the Finnish population. It reported an incidence rate of 7.7 cases per year, aligning with the rarity of OKC reports in the literature.

In addition to finding that patients were older, having a mean age of 46 years, at the time of diagnosis compared with previous reports, the study found that a notable 95% of the OKCs were inflamed, a figure higher than the 76% previously reported. The high prevalence of inflammation supports the theory of late diagnosis, the delay having allowed the undetected cysts to grow larger and given the immune system time to provoke inflammation.

Compared with 15%–63% in the literature, the recurrence rate of OKCs in the study was 21%. The high rate is not fully understood but may have been influenced by the treatment methods, inadequate removal and the presence of microscopic satellite cysts, which were found in 10% of cases, compared with 20%–71% in the literature. Satellite cysts were associated with chronic inflammation and a higher likelihood of recurrence and occurred more commonly in the maxilla. The study also observed a slightly higher incidence of satellite cysts in women. The authors recommended more research to clarify the reasons for recurrences and the relationship between satellite cysts and OKC recurrence.

The authors also suggested that the older age of OKC patients and the higher incidence of inflamed cysts may have contributed to the development of satellite cysts. They emphasised that this highlights the importance of regular radiographic examinations, such as panoramic radiographs, particularly in the second and third decades of life, to facilitate early detection and management of OKCs. They also recommended that the appearance of satellite cysts histopathologically be reported, as they may signify an increased risk of OKC recurrence.

In keeping with the literature, OKCs in the study showed a male predilection and occurred more commonly in the mandible. Among paediatric patients, who made up 6% of the study group, the recurrence rate was 19%, similar to the overall rate for the study. Two patients with recurrent OKCs had Gorlin’s syndrome, a condition already known to be associated with multiple OKCs.

The study’s strength lies in its large sample size and the extensive follow-up period, providing a robust data set for analysis. However, the study faced limitations owing to the use of referral letters for data collection instead of comprehensive patient medical records, which could have offered more detailed clinical and radiological insights.

The study, titled “Appearance and recurrence of odontogenic keratocysts”, was published in the October 2023 issue of Clinical and Experimental Dental Research.

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