Odontogenic cysts: a clinical study of 695 cases.

Abstract

The aim of this study was to analyze the files of 695 consecutive patients operated on under general anesthesia for odontogenic cysts in an adult French teaching hospital for comparison with findings in world surveys. A retrospective survey of cysts of the jaws was undertaken at the Maxillofacial department, Pitié-Salpêtrière University Hospital, Paris, France. Data were retrieved from case notes, imaging, histopathology records and follow-up reports from January 1995 to January 2005. The mean age of patients was 41.8 +/- 15.8 years. There was an overall male to female ratio of 1.86:1. Mandible to maxilla ratio was 3:1. Regarding the mandible, the angle was involved in 36% of the cases, horizontal branch in 32%, parasymphysis in 18%, ramus in 11.6%, coronoid process in 1.5% and condyle in 0.9% (total = 100%). Regarding the maxilla, the canine to canine region was involved in 40% of the cases, premolar and molar region in 45%, and wisdom tooth region in 15% (total = 100%). The three most frequently diagnosed odontogenic cysts were radicular cysts (53.5%), dentigerous cysts (22.3%) and odontogenic keratocysts (19.1%). Together, these three entities represented 94.9% of all odontogenic cysts. The mean number of operation per patient was 1.16 (SD: 0.6, range: 1-10). The mean cumulated duration of hospitalization for one patient was 2.46 days (SD: 1.9, range: 1-28). The mean length of follow-up was 8.4 months (SD: 15.2, range: 0-120). Sixty five percent had a follow-up inferior to 6 months and 18% had no follow-up at all. The two most important findings of this case series are 1) the important number of radicular cysts that could be avoided because most of these cysts develop as a consequence of advanced carious lesions and 2) regarding other types of cysts, the dramatic rate of patients lost to follow-up.

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Abstract: The aim of this study was to analyze the
files of 695 consecutive patients operated on under
general anesthesia for odontogenic cysts in an adult
French teaching hospital for comparison with findings
in world surveys. A retrospective survey of cysts of the
jaws was undertaken at the Maxillofacial department,
Pitié-Salpêtrière University Hospital, Paris, France.
Data were retrieved from case notes, imaging,
histopathology records and follow-up reports from
January 1995 to January 2005. The mean age of patients
was 41.8 ± 15.8 years. There was an overall male to
female ratio of 1.86:1. Mandible to maxilla ratio was
3:1. Regarding the mandible, the angle was involved
in 36% of the cases, horizontal branch in 32%,
parasymphysis in 18%, ramus in 11.6%, coronoïd
process in 1.5% and condyle in 0.9% (total = 100%).
Regarding the maxilla, the canine to canine region was
involved in 40% of the cases, premolar and molar
region in 45%, and wisdom tooth region in 15% (total
= 100%). The three most frequently diagnosed
odontogenic cysts were radicular cysts (53.5%),
dentigerous cysts (22.3%) and odontogenic keratocysts
(19.1%). Together, these three entities represented
94.9% of all odontogenic cysts. The mean number of
operation per patient was 1.16 (SD: 0.6, range: 1-10).
The mean cumulated duration of hospitalization for one
patient was 2.46 days (SD: 1.9, range: 1-28). The mean
length of follow-up was 8.4 months (SD: 15.2, range:
0-120). Sixty five percent had a follow-up inferior to 6
months and 18% had no follow-up at all. The two most
important findings of this case series are 1) the
important number of radicular cysts that could be
avoided because most of these cysts develop as a
consequence of advanced carious lesions and 2)
regarding other types of cysts, the dramatic rate of
patients lost to follow-up. (J. Oral Sci. 48, 59-62, 2006)
Keywords: odontogenic cyst; dentigerous cyst;
keratocyst; orthokeratinized odontogenic
cyst
Introduction
Odontogenic cysts are rare entities that appear in tooth-
bearing areas. The importance of a correct diagnosis is that
some variants, i.e. keratocysts are aggressive and subject
to recurrence.
Surprisingly there have been few studies on the precise
prevalence of these lesions in Europe. However, theses data
are important to assess geographic differences. They are
also helpful in creating a syllabus for both dental and
medical students. Finally, these data are valuable to improve
the information that has to be given to patients with
nonspecific clinical and radiographic lesions.
The purpose of this study was to analyze the files of 695
consecutive patients operated on under general anesthesia
in an adult French teaching hospital for comparison with
findings in world surveys.
Materials and Methods
A retrospective survey of odontogenic cysts based on
the classification published by Kramer et al. (1), was
undertaken at the department of maxillofacial surgery,
Pitié-Salpêtrière University Hospital, Paris, France. The
records of 695 consecutive adult patients operated on
under general anesthesia for odontogenic cysts were
Journal of Oral Science, Vol. 48, No. 2, 59-62, 2006
Original
Correspondence to Dr. Jean-Paul Meningaud, Service de chirurgie
maxillo-faciale, CHU Pitié-Salpêtrière, 47 bd de l'hôpital, 75651
Paris cedex 13, France
Tel: +33-1-42-16-13-03
Fax: +33-1-42-16-13-69
E-mail: meningaud@noos.fr
Odontogenic cysts: a clinical study of 695 cases
Jean-Paul Meningaud, Nicoleta Oprean, Poramate Pitak-Arnnop
and Jacques-Charles Bertrand
Department of Maxillofacial Surgery, Teaching Pitié-Salpêtrière Hospital, Pierre et Marie Curie University,
Paris, France
(Received 28 February and accepted 30 May 2006)

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included in the study. Data were retrieved from case notes,
imaging, histopathology records and follow-up reports
from January 1995 to January 2005. In every case the
following information was obtained: age, gender, imaging
procedures, location of the lesion, surgical treatment,
histopathologic diagnosis, number of operations for the
same lesion, cumulated duration of the hospitalization for
one patient, and length of follow-up. Information was
analyzed using descriptive statistics.
Results
The mean age of patients was 41.8 ± 15.8 years. There
was an overall male to female ratio of 1.86:1. The imaging
procedures were: 100% of orthopantomogram, 43% of ct-
scan. An MRI was prescribed for only 3 patients. The
overall mandible to maxilla ratio was 3:1. Regarding the
mandible, the angle (wisdom tooth region) was involved
in 36% of the cases, horizontal branch (premolar and
molar region) in 32%, parasymphysis (canine to canine
region) in 18%, ramus in 11.6%, coronoïd process in 1.5%
and condyle in 0.9% (total = 100%). Regarding the maxilla,
canine-to-canine region was involved in 40% of the cases,
premolar and molar region in 45%, and wisdom tooth
region in 15% (total = 100%). All the cysts were enucleated
except for 1 orthokeratocyst and 1 parakeratocyst. These
two cases lead to a mandibulectomy.
The three most frequently diagnosed odontogenic cysts
were apical and lateral cysts (53.5%), dentigerous cysts
(22.3%) and odontogenic keratocysts (19.1%). Together,
these three entities represented 94.9% of all odontogenic
cysts. Eight odontogenic keratocysts were associated with
a nevoid basal cell carcinoma syndrome. Table 1
summarizes the relative frequencies of the diverse lesions.
Among the keratocysts, 78 out 133 had a more precise
diagnosis: 72% of these were classified as parakeratocysts,
12% as orthokeratocysts and 16% as ortho + para
keratocysts (total = 100%). Three entities were not found:
gingival cyst of infants, gingival cyst of the adult and
eruption cysts, as this case series investigated only adults
operated on under general anesthesia.
The mean number of operations per patient was 1.16 (SD:
0.6, range: 1-10). The relative incidence of the three most
diagnosed cysts operated on one time was: apical and
lateral cysts (58.0%), dentigerous cysts (24.5%),
odontogenic keratocysts (12.2%). The relative incidence
of the three most diagnosed cysts operated on more than
one time was as follows: odontogenic keratocysts (72.5%),
apical and lateral cysts (18.7%), dentigerous cysts (3.7%).
The mean cumulated duration of hospitalization for one
patient was 2.46 days (SD: 1.9, range: 1-28). The relative
incidence of the three most diagnosed cysts with a
cumulated duration of hospitalization inferior to 2 days was:
apical and lateral cysts (58.7%), dentigerous cysts (23.6%),
odontogenic keratocysts (12.2%). The relative incidence
of the three most diagnosed cysts with a cumulated duration
of hospitalization superior or equal to 3 days was:
odontogenic keratocysts (39.5%), apical and lateral cysts
(38.4%), dentigerous cysts (18.1%).
Table 1 Frequency of odontogenic cysts

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The mean length of follow-up was 8.4 months (SD:
15.2, range: 0-120). Seventeen percent had a follow-up
superior to 6 months (apical and lateral cysts: 38.4%,
odontogenic keratocysts: 34.1%, dentigerous cysts: 21.3%),
65% percent had a follow-up inferior to 6 months (apical
and lateral cysts: 60.12%, dentigerous cysts: 22.5%,
odontogenic keratocysts: 12.6%) and 18% had no follow-
up at all (apical and lateral cysts: 68.8%, dentigerous
cysts: 17.6%, odontogenic keratocysts: 9.6%).
Discussion
The most important finding of this case series is the
problem of the dramatic rate of patients lost to follow-up.
It is an important concern because the risk of recurrence
is not negligible. These cysts may be asymptomatic during
a long period of time, leading to a significant destruction
of bone. The follow-up should last at least until the complete
reossification of the cyst cavity, i.e. at least two years. It
involves performing an orthopanthomogram every 6 months
and a CT scan in case of doubt. The follow-up should be
even longer for odontogenic keratocyst (notably
parakeratinized). But even regarding the specific diagnosis
of keratocysts, Chirapathomsakul et al. (2) reported a rate
of 39 % (20 out 51) of patients lost to follow-up after a
short period of time (less than 1 year). Concerning this kind
of cyst, most recurrences presented within 5 years, but late
recurrences did occur even after 25 years (3). A follow-
up every two years seems appropriate. The explanation for
this important rate of patients lost to follow-up is the usual
asymptomatic features of these cysts. The information
may be insufficient or not well understood. The rate of
patients lost to follow-up is probably more important in
public hospitals where the percentage of patients with
social problems is higher. Subsequently, our data about the
recurrence rate may not delineate the reality and did not
allow us to make comparisons between types of cysts.
Radicular cysts were the most frequently diagnosed
lesions. This is an important concern too, because most
of these cysts develop as a consequence of advanced
carious lesions and thus in a large number of cases may
be prevented. The rate for radicular cysts found in our study
(53.5%) lies within the range of 52% reported by Shear
(4) and 56.9% reported by Kreidler et al. (5).
The male predominance is consistent with the findings
of other studies (6,7) in which it has been considered that
men are more likely to neglect their hygiene and to have
trauma of the maxillary anterior teeth.
The relative incidence of cyst of the three most common
cysts found in our study (radicular cyst, dentigerous,
keratocyst) is consistent with other studies such as
Mosqueda et al. (6) from Mexico (39.9%, 33%, 21.5%),
Ledesma-Montes (7) (38.8%, 35.5%, 18.8%) from Mexico
too, Daley et al. (8) from Canada (65.1%, 24%, 4.8%),
Nakamura (9) from Japan (41.2%, 27%, 7.7%), Shear (4)
from South Africa (52.3%, 16.6%, 11.2%), Arotiba et al.
(10) from Nigeria (61.9%, 19%,14.3%), Kreidler et al. (5)
from Germany (56.9%, 21.3%, 10.6%) and Bataineh et al.
(11) from Jordan (41.7%, 24.8%, 6.0%). Unlike most
studies, our cases are not selected directly from the records
of a pathology laboratory, but from the records of the
patients operated on under general anesthesia. Comparing
only cysts removed under general anesthesia to other
general studies of odontogenic cysts tends to bias the data.
Nevertheless, it is interesting to note that this does not
seem to affect the relative incidence of the three most
common cysts. Another possible bias in this study is that
the histopathology of the cysts was not reviewed for
verification of the diagnosis. However, all the pathologists
that made histopatologic diagnoses have had a formal
training in odontogenic tumors and cyst pathology.
Discrepancies in diagnoses of odontogenic lesions, between
general surgical pathologists and oral pathologists are
frequent. Besides, the reviewing could have made possible
the precise diagnosis of all orthokeratocyst and
parakeratocyst. This distinction was not usual in our files
before 2000.
Koseoglu et al. (12) (Turkey) and Oji (13) (Nigeria) found
a different relative incidence regarding dentigerous cysts
and keratocysts, but their case series included only 90
and 20 patients, respectively. Bhaskar (14) (USA) found
the same relative incidence but with a very small number
of keratocysts (1.7%). The lack of uniform criteria at the
time of the study may explain this discrepancy.
The orthopanthomogram is the chief imaging procedure
to track the cysts. The CT scan is currently more demanded.
It is considered as the best imaging procedure to assess
the size of the cyst and the position relative to the dental
nerve and the dental apices. The MRI is rarely demanded,
except when there is a doubt with a tumor. In this case,
MRI and notably contrast enhanced MRI is able to provide
decisive information (15).
Mandibulectomies are exceptional, even in the case of
very big cysts. The enucleation in one piece is the rule.
The mandibulectomy is the exception. When there is a doubt
with a tumor, a biopsy is recommended.
References
1. Kramer IRH, Pindborg JJ, Shear M (1992)
Histological typing of odontogenic tumors. 2nd ed,
Springer-Verlag, Berlin, 34-42
2. Chirapathomsakul D, Sastravaha P, Jansisyanont P
(2006) A review of odontogenic keratocysts and the

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62
behavior of recurrences. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 101, 5-9
3. Stoelinga PJ (2001) Long-term follow-up on
keratocysts treated according to a defined protocol.
Int J Oral Maxillofac Surg 30, 14-25
4. Shear M (1992) Cysts of the oral regions. 3rd ed,
Wright, Oxford, 75-98
5. Kreidler JF, Raubenheimer EJ, van Heerden WF
(1993) A retrospective analysis of 367 cystic lesions
of the jaw- the Ulm experience. J Craniomaxillofac
Surg 21, 339-341
6. Mosqueda-Taylor A , Irigoyen-Camacho ME , Diaz-
Franco MA , Torres-Tejero MA (2002) Odontogenic
cysts. Analysis of 856 cases. Med Oral 7, 89-96
7. Ledesma-Montes C , Hernandez-Guerrero JC ,
Garces-Ortiz M (2000) Clinico-pathologic study
of odontogenic cysts in a Mexican sample
population. Arch Med Res 31, 373-376
8. Daley TD, Wysocki GP, Pringle GA (1994) Relative
incidence of odontogenic tumors and oral and jaw
cysts in a Canadian population. Oral Surg Oral Med
Oral Pathol 77, 276-280
9. Nakamura T, Ishida J, Nakano Y, Ishii T, Fukumoto
M, Izumi H, Kaneko K (1995) A study of cysts in
the oral region. Cysts of the jaw. J Nihon Univ Sch
Dent 37, 33-40
10. Arotiba JT, Lawoyin JO, Obiechina AE (1998)
Pattern of occurrence of odontogenic cysts in
Nigerians. East Afr Med J 75, 664-666
11. Bataineh AB, Rawashdeh MA, Al Qudah MA (2004)
The prevalence of inflammatory and developmental
odontogenic cysts in a Jordanian population: a
clinicopathologic study. Quintessence Int 35, 815-
819
12. Koseoglu BG, Atalay B, Erdem MA (2004)
Odontogenic cysts: a clinical study of 90 cases. J
Oral Sci 46, 253-257
13. Oji C (1999) Statistical observations on jaw cysts
in Enugu, Nigeria, 1987-1996. Odontostomatol
Trop 22, 33-36
14. Bhaskar SN (1968) Oral pathology in the dental
office: survey of 20,575 biopsy specimens. J Am
Dent Assoc 76, 761-766
15. Hisatomi M, Asaumi J, Konouchi H, Shigehara H,
Yanagi Y, Kishi K (2003) MR imaging of epithelial
cysts of the oral and maxillofacial region. Eur J
Radiol 48,178-182