Odontogenic keratocyst: Review of 256 cases for recurrence and clinicopathologic parameters

Conservative Treatment Protocol for Keratocystic Odontogenic Tumour: a Follow-up Study of 3 Cases

Background

The keratocystic odontogenic tumour is classified as a developmental cyst derived from the enamel organ or from the dental lamina. The treatment of keratocystic odontogenic tumour of the jaw remains controversial. The aim of this study was to report the outcome of our conservative treatment protocol for keratocystic odontogenic tumour.

Methods

Three patients with different complaints referred to Oral and Maxillofacial Surgery Clinic, Faculty of Dentistry, Selçuk University. Initial biopsy was carried out in all patients and keratocystic odontogenic tumours was diagnosed subsequent to histopathological examination. The patients with keratocystic odontogenic tumours were treated by enucleation followed by open packing. This conservative treatment protocol was selected because of existing young aged patients. The average follow-up duration of the cases was 2 years.

Results

Out of 3 cases, 2 lesions were present in mandible and 1 lesion in maxilla. There was no evidence of recurrence during follow-up. All the cases were monitored continuously with panoramic radiographs, computed tomography and clinical evaluations.

Conclusions

This conservative treatment protocol for keratocystic odontogenic tumours, based on enucleation followed by open packing would be a possible choice with a view of offering low recurrence rate and low morbidity rate particularly in young patients.

Endoscopic approach to benign lesion involving the mandibular condyle

Benign lesions involving the mandibular condyle are rare. Odontogenic keratocyst has been always an interesting subject to debate since Philipsen first described it as a distinct entity in 1956. Nevertheless, the large variability and the lack of homogeneity between patients in the different studies did not allow to develop universally recognized guidelines for the keratocyst odontogenic tumor treatment. The aim of this article was to present a new surgical technique to approach high-dimension benign lesion located at the level of the mandibular ramus and condyle, consisting enucleation and curettage under endoscopic vision.

Parameters in panoramic radiography for differentiation of radiolucent lesions

Objective:

The aims of this study were to establish parameters in panoramic radiography for interpretation of unilocular radiolucent lesions, and to compare the accuracy of diagnoses given by examiners before and after using these parameters.

Material and Methods:

In Part I, 12 specialists analyzed 24 images and the diagnostic criteria used by each examiner to make correct diagnoses were used to build a list of basic radiographic parameters for each pathology (ameloblastoma, keratocystic odontogenic tumor, dentigerous cyst, and idiopathic bone cavity). In Part II, this list was used by 6 undergraduate students (Un), 8 recently graduated dentists (D), 3 oral pathologists, 3 stomatologists, 3 oral radiologists, and 3 oral surgeons to diagnose the corresponding pathologies in the other set of 24 panoramic radiographs (T2). The same analysis occurred without using this list (T1). The method of generalized estimating equations (GEE) was used in order to estimate the probability of making a correct diagnosis depending on the specialty of the examiner, type of lesion, and moment of the evaluation, T1 or T2 (before or after they had access to the list of parameters, respectively).

Results:

Higher values were obtained for the probability (GEE) of making a correct diagnosis on T2; the group Un presented the highest improvement (14.6 %); no differences between the probabilities were observed either between Un and D, or among the different groups of specialists.

Conclusions:

The use of panoramic radiographic parameters did allow improving the diagnostic accuracy for all groups of examiners.

A radiolucent lesion crossing the midline in maxilla: a rare presentation of odontogenic keratocyst in young patient

Odontogenic Keratocyst (OKC) is a developmental non-inflammatory odontogenic cyst which is proposed to be arising from cell rests of dental lamina. Among the jaw cysts OKCs account for third most common following radicular and dentigerous cyst. Most of the studies have stated that posterior part of the mandible is the most common site, but there are inconsistencies regarding the prominent location of OKCs in the maxilla. Very few studies and cases are reported with OKCs crossing maxillary midline. If do occur they are in older individuals. According to WHO reclassification, this cyst is considered as Keratocystic Odontogenic Tumour (KCOT) because of its neoplastic nature. This article describes a rare site of occurrence of this lesion especially in young patient.

Characterization and management of the keratocystic odontogenic tumor in relation to its histopathological and biological features

Keratocystic odontogenic tumor (KCOT), formerly referred to as odontogenic keratocyst, is a benign neoplasm of odontogenic origin which may present an aggressive and infiltrative behavior leading to high recurrence rates. A review of the various treatment modalities, ranging from simple enucleation to radical surgery is portrayed in relation to clinical, radiological, histopathological and molecular features. Although prognostic factors based on clinico-pathologic and immunohistochemical findings for determining the potential for recurrence of KCOT still remains unclear, its use for determining the potential for recurrence of KCOT after surgical treatment may become important to successfully manage this neoplasm's aggressive behavior. The key element for future management of KCOTs will probably be based on thorough knowledge of the biological basis of this tumor, thereby enabling a more tailored treatment approach.

Orthokeratinized odontogenic cyst: a clinicopathologic study of 61 cases

CONTEXT

Orthokeratinized odontogenic cyst (OOC) is a relatively uncommon developmental cyst comprising about 10% of cases that had been previously coded as odontogenic keratocysts. Odontogenic keratocyst was designated as keratocystic odontogenic tumor (KCOT) in the new World Health Organization classification and OOC should be distinguished from KCOT for differences in histologic features and biologic behavior.

OBJECTIVE

To analyze the clinicopathologic features of 61 cases of OOC in a Chinese population.

DESIGN

Clinicopathologic analysis was performed on 61 cases of OOC. Immunohistochemical expression of Ki-67 and p63 was evaluated in 15 OOCs and 15 typical KCOTs.

RESULTS

The 61 patients with OOC ranged from 13 to 75 years (average, 38.93 years). The lesions developed mainly in the third and fourth decades (57.38%) with a distinct predilection for males (72.13%). Six (9.84%) lesions were found in the maxilla and 55 (90.16%) in the mandible. The most common sites were in the mandibular molar and ramus region. Of the 54 cases with radiographic record, 47 (87.04%) were unilocular and 7 (12.96%) were multilocular radiolucencies. Twenty-seven of the 54 cysts were associated with an impacted tooth. Follow-up of 42 patients revealed no recurrence during an average period of 76.8 months after surgery. Compared with KCOTs, expression level of Ki-67 and p63 was significantly lower in OOCs, suggesting a lower proliferative activity.

CONCLUSION

Orthokeratinized odontogenic cyst is clinicopathologically distinct from KCOT and should constitute its own clinical entity.

A case of orthokeratinized odontogenic cyst suspected to be a radicular cyst

This report describes a case of orthokeratinized odontogenic cyst arising in the mandibular molar region of a 39-year-old man. Under the initial clinical diagnosis of radicular cyst, root canal treatment was performed on the mandibular right second molar. The treatment that continued for six months did not achieve healing. Subsequently surgical intervention was selected since the tooth fracture was found, and the prognosis was judged to be poor. After atraumatic tooth extraction, the apical cystic lesion was enucleated, and the tooth was replanted. A definite diagnosis of orthokeratinized odontogenic cyst was made by histopathological examination of the biopsy specimen. The radiograph taken seven months after the operation showed an improvement in the radiolucent lesion. No clinical signs of tooth mobility, pain, and swelling were present. The tooth was then successfully retained with the final restoration. Careful follow-up is needed in order to detect any signs of recurrence.

Actual Proliferating Index and p53 protein expression as prognostic marker in odontogenic cysts

BACKGROUND

The purpose of this study was to evaluate the biological aggressiveness of odontogenic keratocyst/keratocystic odontogenic tumour (KCOT), radicular cyst (RC) and dentigerous cyst (DC) by observing the actual proliferative activity of epithelium, and p53 protein expression.

METHODS

The actual proliferative activity was measured by Ki-67 Labelling Index and argyrophilic nucleolar organizing regions (AgNOR) count per nucleus. The p53 protein expression was also evaluated.

RESULTS

Ki-67 positive cells were observed higher in suprabasal cell layers of KCOT with uniform distribution, a few of them were predominantly observed in basal cell layer in RC and DC. The AgNOR count was significantly higher in suprabasal cell layers of KCOT. The actual proliferative activity was noted to be higher in suprabasal cell layers of KCOT. The p53 immunolabelling was dense and scattered in basal and suprabasal cell layers in KCOT. The weakly stained p53 positive cells were observed diffusely distributed in KCOT, whereas they were mainly seen in basal cell layer of RC and DC.

CONCLUSION

The quantitative and qualitative differences of the proliferative activity and the p53 protein expression in sporadic KCOT may be associated with intrinsic growth potential that could play a role in its development and explain locally aggressive biological behaviour. AgNOR count and p53 protein detection in odontogenic lesions can be of great consequence to predict the biological behaviour and prognosis.

Developmental odontogenic cysts of jaws: a clinical study of 245 cases

BACKGROUND AND AIMS

The aim of this study was to investigate the relative frequency of developmental odontogenic cysts in an Iranian population.

MATERIALS AND METHODS

In this study 245 cysts from both jaws, treated in the Faculty of Dentistry at Tabriz University of Medical Sciences during a 10-year period from 1998 to 2008, were analyzed in order to evaluate the incidence of such cysts. We had permission from all the patients. Case histories of 65% of male and 35% of female patients were analyzed. The age of the patients varied from 14 to 64 years, with an average of 33.21 ± 10.89.

RESULTS

In this 10-year study of odontogenic cysts, 97 cases were developmental odontogenic cysts with the following inci-dence: dentigerous cyst, 44%; odontogenic keratocyst, 36%; primordial cyst, 9%; Gorlin cyst, 2%; lateral periodontal cyst, 3%; eruption cyst, 3%; and gingival cyst, 3% (adults 2%, infants 1%). A total of 60% of the cysts were found in the mandible and 40% in the maxilla. Regarding the mandible, the molar region was involved in 47% of the cases, premolar region in 33% and anterior region in 20% (total = 100%). Regarding the maxilla, the canine-to-canine region was involved in 52% of the cases, premolar region in 20% and molar region in 28% (total = 100%).

CONCLUSION

An important finding in this study was the fact that 39% of the jaw cysts were developmental odontogenic cysts and the most common developmental odontogenic cysts were dentigerous cyst and OKC (odontogenic keratocyst).

[Imaging of odontogenic tumors of the maxilla]

Odontogenic tumors of the maxilla are frequent, mainly represented by cysts of the jaw. However, this group of tumors include a large number of potentially intricate pathologies whose evolution is dominated by frequent recurrences justifying long-term follow-up. When such a lesion is discovered, evaluation of imaging features combined with an extensive knowledge of the different patterns of other lesions (particularly their potentially evolutive patterns related to growth) can often suggest the diagnosis. While definitive diagnosis frequently relies on histology, it is not rare that the patterns are so intricate that final diagnosis is based on a correlation between clinical, imaging and histological findings.

Decompression and cystectomy of the odontogenic keratocysts of the mandible: a clinical study

OBJECTIVES

Owing to the aggressive nature of OKC's if one could stop or even reverse the growth of the cyst with a simple procedure like decompression, regardless of the histologic type, it would be an alternative to radical and disfiguring surgery.

METHODS

Eight patients who were diagnosed with Odontogenic keratocyst of the mandible were chosen and the first stage of treatment being, insertion of the decompression stent into the most prominent or dependent part of the cystic cavity. Then based on assessment of regular second monthly OPG radiograph the second stage ie. Enucleation of the cyst and treatment of the cystic cavity with Carnoy's solution was carried out, when the size of the cystic cavity had decreased.

RESULTS

The radiographs of all the patients were analyzed at a two month interval and compared with the pre operative radiograph. The percentage of change in radiodensity of the lesion ranged from 35.15% to 66.16% with a mean decrease of 53.85%. This also indicated that the quantum of bone regeneration which occurred simultaneously and as observed during the cystectomy procedure was commendable.

CONCLUSION

Reduction of surgical morbidity while preserving anatomy and function, is the greatest advantage of decompression, however one should not forget the emphasis on the value of long term studies needed to be carried out with regular follow-up, to keep a check on those patients treated with decompression.

Keratocystic odontogenic tumor invading the right maxillary sinus: a case report

Keratocystic odontogenic tumor (KCOT) is a benign intraosseous neoplasm of the jaw. Involvement of the maxillary sinus is an unusual presentation. We present the case of a 23-year-old man with extensive KCOT and impacted third molar in the right maxillary sinus. The clinical, radiological, and histological features of this tumor and its surgical management are discussed.

Keratocystic odontogenic tumor: a retrospective study of 183 cases

In 2005, the WHO Working Group considered odontogenic keratocyst (OKC) to be a tumor and recommended the term keratocystic odontogenic tumor (KCOT), separating the lesion from the orthokeratinizing variant, which is now considered an odontogenic cyst. We analyzed the clinicopathological features of KCOTs encountered over a period of 28 years at Meikai University Hospital. The diagnosis was confirmed by reevaluation of hematoxylin and eosin-stained slides on the basis of the 2005 WHO Classification. Clinical history was also taken into consideration. A total of 183 KCOTs were found, and the two genders were affected almost evenly (51.3% male; 48.7% female; male to female ratio 1.05 to 1). Patient age at the time of diagnosis ranged from 6 to 78 years, with a peak in the third decade of life (mean age: 32.8 years). The mandible was the site of occurrence of 70.5% of tumors; 16.4% occurred in the maxilla and 13.1% in both. Association with the nevoid basal cell carcinoma syndrome (NBCCS) was found in 6.0% of all tumors, and recurrence was found in 13.1% of patients. We found that tumors that initially appeared in the maxilla alone had a higher recurrence rate than those that first appeared in the mandible alone. Pathological examination of KCOT is important to avoid misdiagnosis and provide appropriate treatment and follow-up.

Keratocystic odontogenic tumor: a 10-year retrospective study of 83 cases in an Iranian population

A retrospective analysis was conducted on patients diagnosed with and treated for keratocystic odontogenic tumor (KCOT) at Mashhad School of Dentistry between 1996 and 2006. The patients comprised 44 men and 30 women with a mean age of 27.08 years. Among the total of 83 lesions, 56 (67.5%) occurred in the mandible and 27 (32.5%) in the maxilla. Swelling tended to be the most common complaint (45.8%), while 24.1% of the lesions were diagnosed incidentally. Six patients (8.1%) with a total of 15 lesions had nevoid basal cell carcinoma syndrome; 28 lesions (33.7%) were associated with an impacted tooth, and 12 (14.5%) presented daughter cysts. Sixty-six KCOTs were treated by enucleation [5 recurrences (7.6%)], 6 by marsupialization [2 recurrences (33.3%)] and 11 by marsupialization followed by enucleation (no recurrences). KCOTs in the mandible showed a higher recurrence rate than those in the maxilla (10.7% vs 3.7%). Although the demographics of Iranian patients are closely similar to those of other nationalities, in this series KCOTs tended to develop in younger patients with a peak in teenagers. The posterior region of the mandible showed the highest likelihood of KCOT occurrence and recurrence. Marsupialization followed by enucleation resulted in the lowest recurrence rate.

Vergleichende klinische und immunhistochemische Charakterisierung keratozystischer odontogener Tumoren und Ameloblastome im Hinblick auf das Rezidivrisiko

BACKGROUND

With the new term "keratocystic odontogenic tumour" (KCOT) keratocyts are even in the nomenclature a close differential diagnosis to ameloblastomas (A).

PURPOSE

Recurrence of KCOT and A were retrospectively compared with regard to treatment and immunohistochemical markers of cell cycle and migration and cell architecture.

PATIENTS AND METHODS

Biopsies harvested over a period of 22 years of 101 patients (86 KCOT, 15 A) were examined. The histopathological slides were stained with H&E and with the immunohistochemical markers: Cyclin D1, Collagen IV, p16, Cox-2-Laminin-5 and Tenascin-C.

RESULTS

Mean age KCOT 47 years (range 14-80 years), A 41 years (range 16-79 years). Gender KCOT: m:f =2:1; A: m:f = 3:2. Region of origin mandible with predilection of the angle and the ramus: KCOT: 76; A: 12. Maxilla: KCOT: 18; A: 3. Multiple lesions were found in 5 KCOT patients. Treatment primary KCOT: cystectomy (46), cystostomy (6), cystectomy and curettage (17), cystectomy and marginal ostectomy (14), resection (11). A: resection (10), enucleation (5). Recurrence rate KCOT: 11,7% after 5,5 years. Recurrence after: cystostomy (4), cystectomy (6), cystectomy and curettage (3), cystectomy and marginal ostectomy (2). A: no recurrences. Immunohistochemistry Cell cycle associated and extracellular matrix proteins did not differ in quantity in KCOT and A, and did also not differ in recurrent and non-recurrent KCOT.

CONCLUSIONS

1. KCOT are in the own cohort more likely recurrent than A. 2. Recurrence rate of KCOT can not be predicted by the used (most common) markers of cell cycle, migration and modulation of architecture. 3. Higher recurrence rate of KCOT in the patients examined is proposed due to less extensive resection.

Effects of mandibular odontogenic keratocyst surgery and removable partial prostheses on masticatory performance

STATEMENT OF PROBLEM

Surgical treatment of odontogenic keratocysts often results in tooth loss. However, information about the effects of different surgical methods and postoperative prosthetic therapy on masticatory performance is lacking.

PURPOSE

The purpose of this study was to compare tooth loss following odontogenic keratocyst treatment by enucleation, segmental mandibulectomy with reconstruction, or marsupialization, and the resultant effect on masticatory performance with and without removable partial dentures (RPDs).

MATERIAL AND METHODS

Patients with odontogenic keratocysts of the mandible were treated with either enucleation (n=33), segmental mandibulectomy and immediate autogenous bone reconstruction (n=18), or marsupialization in combination with secondary enucleation (n=9). Clinical and radiographic examinations were used to assess the number of teeth with cyst involvement preoperatively and the number of teeth lost following cyst treatment. Masticatory performance with peanuts was measured after cyst treatment both with and without an RPD. The differences in the number of the teeth involved preoperatively and lost postoperatively were compared among the 3 groups with a chi square test for trend. The absorbance value (reflecting masticatory performance) difference among the 3 groups preprosthesis and postprosthesis was analyzed using a 1-way analysis of variance (ANOVA), respectively. The pre- and postprosthetic comparison was made within each group, and a paired t test was used. Age was compared using 1-way ANOVA among 3 groups. Gender was compared using the chi square test (alpha=.05).

RESULTS

Although the average number of teeth involved preoperatively with the cyst was similar among the 3 treatment groups, the number of teeth lost following marsupialization was significantly less than the number lost following enucleation or segmental mandibulectomy. Prior to provision of an RPD, mean masticatory performance (mean absorbance value of 0.36+/-0.08) in subjects receiving segmental mandibulectomy was significantly lower than for subjects receiving enucleation (0.52+/-0.15) or marsupialization (0.89+/-0.12) (P<.01). Provision of an RPD significantly increased masticatory performance in subjects who were treated by enucleation or segmental mandibulectomy (P<.01).

CONCLUSION

Masticatory performance following odontogenic keratocyst surgery is related to the number of lost teeth, which is a function of the operative method used. Restoration with an RPD postoperatively may improve masticatory function when multiple teeth are lost following enucleation or segmental mandibulectomy.

Imaging characteristics of neoplasms and other lesions of the jawbones

Odontogenic tumors of the jawbones arise in the tissues of the odontogenic apparatus. Although many odontogenic tumors and tumorlike lesions may be asymptomatic, they can become severe enough to cause pain, swelling, paresthesias, facial disfigurement, and various dental problems. The evaluation of lesions involving the jawbones can be challenging due to lack of familiarity with the imaging and clinical features of the disease. Further confusing the diagnosis is the fact that some benign odontogenic tumors may exhibit an aggressive and destructive behavior that can fallaciously suggest a malignant lesion. Careful consideration of the patient's history and the location of the lesion within the affected jawbone, its borders, internal architecture, and its relationship to adjacent structures generally makes it possible to narrow the differential diagnosis.

Odontogenic keratocysts arise from quiescent epithelial rests and are associated with deregulated hedgehog signaling in mice and humans

Odontogenic keratocysts in humans are aggressive, noninflammatory jaw cysts that may harbor PTCH1 mutations, leading to constitutive activity of the embryonic Hedgehog (Hh) signaling pathway. We show here that epithelial expression of the Hh transcriptional effector Gli2 is sufficient for highly penetrant keratocyst development in transgenic mice. Mouse and human keratocysts expressed similar markers, leading to tooth misalignment, bone remodeling, and craniofacial abnormalities. We detected Hh target gene expression in epithelial cells lining keratocysts from both species, implicating deregulated Hh signaling in their development. Most mouse keratocysts arose from rests of Malassez--quiescent, residual embryonic epithelial cells that remain embedded in the periodontal ligament surrounding mature teeth. In Gli2-expressing mice, these rests were stimulated to proliferate, stratify, and form a differentiated squamous epithelium. The frequent development of keratocysts in Gli2-expressing mice supports the idea that GLI transcription factor activity mediates pathological responses to deregulated Hh signaling in humans. Moreover, Gli2-mediated reactivation of quiescent epithelial rests to form keratocysts indicates that these cells retain the capacity to function as progenitor cells on activation by an appropriate developmental signal.

Odontogenic Keratocyst of mandible

The Odontogenic Keratocyst is a developmental odontogenic cyst and deserves special attention because of its peculiar histopathologic features and biologic behavior. It is believed that the Odontogenic Keratocyst arises from the proliferation of remnants of dental lamina. It is usually asymptomatic, and solitary lesion, however, it may be associated with Nevoid Basal Cell Carcinoma Syndrome. This work aimed to present a case of a very extensive Odontogenic Keratocyst in a 28-year-old woman.

Nevoid basal cell carcinoma syndrome

Binkley and Johnson first reported this syndrome in 1951. But it was in 1960, Gorlin-Goltz established the association of basal cell epithelioma, jaw cyst and bifid ribs, a combination which is now frequently known as Gorlin-Goltz syndrome as well as Nevoid Basal Cell Carcinoma Syndrome (NBCCS). NBCCS is inherited as an autosomal dominant trait with high penetrance and variable expressivity. NBCCS is characterized by variety of cutaneous, dental, osseous, opthalmic, neurologic and sexual abnormalities. One such case of Gorlin-Goltz syndrome is reported here with good illustrations.

Conventional and indirect digital radiographic interpretation of oral unilocular radiolucent lesions

OBJECTIVES

To compare the diagnostic processes for the main unilocular radiolucent lesions of the mandible in the presence of the following variables: conventional and digital radiography, specialization of the examiner and type of lesion.

METHODS

Twenty-four panoramic radiographs were selected from the archives of the AC Camargo Hospital (São Paulo, Brazil), aiming at comparing the diagnostic processes for similar unilocular radiolucent lesions of the mandible, with the following histopathological diagnosis: six ameloblastomas, six dentigerous cysts, six keratocysts and six traumatic bone cysts. The radiographs were scanned and processed using the Trophy 2000 software. Three specialists, each from four related areas (pathologists, stomatologists, radiologists and oral surgeons), randomly evaluated the radiographs before and after digitalization.

RESULTS

The kappa statistic showed a high level of agreement between results obtained using the two radiographic techniques. This means that, in general, the examiners diagnosed the same cases correctly or incorrectly regardless of the method used.

CONCLUSIONS

Based on generalized estimating equations, it was concluded that the probability of correct diagnosis does not depend on the kind of lesion, on the radiographic technique or on the specialization of the examiner. In view of the differing opinions of the specialists regarding the diagnostic validity of some software features available and of the results obtained in indirect digital technique, it may be reasonable to reconsider its use for diagnosis of bone pathology.

Odontogenic keratocyst in maxillary sinus with invasive behaviour

Odontogenic keratocyst is a cystic lesion characterized by a high rate of recurrence. This report describes a rare case of ciliated epithelium-lined odontogenic keratocyst in the maxilla of a 27-year-old female. Panoramic radiography showed a lytic lesion on the right maxilla associated with an impacted molar tooth. Computerized tomography image revealed the involvement of the lesion with the right maxillary sinus, destroying the sinus floor. Histopathologically, the typical keratinized epithelial-lined cyst of odontogenic keratocyst abruptly changed into a ciliated epithelium, suggesting the fusion of both these epithelia rather a metaplastic transformation. The biological behaviour of odontogenic keratocysts is discussed.

A review of odontogenic keratocysts and the behavior of recurrences

OBJECTIVE

The purpose of this study is to report experiences of odontogenic keratocysts (OKCs) and analyze information regarding recurrences to better understand the nature of recurrences.

STUDY DESIGN

Fifty-one cases of OKC treated at the Faculty of Dentistry, Chulalongkorn University, from 1988 to 2003 were studied retrospectively. Clinicoradiographic features, histologic features, and methods of treatment were reviewed. Recurrences were analyzed and compared with respect to sites of involvement, relationship to the remaining teeth, and methods of treatment.

RESULTS

OKCs occurred predominantly in the 11- to 40-year-old age group. The body-angle-ramus area of mandible was the most common site of occurrence. Radiographically, the unilocular to multilocular radiolucency ratio was 2.5:1. Multilocular lesions occurred more frequently in the mandible (P < .05). Most of the lesions were diagnosed histologically as parakeratinized OKC (93.7%). The patients were followed from 1-14.6 years. However, 20 patients were lost to follow-up after a short period of time, and recurrences were found in 7 out of 31 cases (22.6%). The recurrent tumors occurred more frequently in patients who had an OKC associated with the remaining teeth and were treated by enucleation or enucleation with adjuvant therapy.

CONCLUSIONS

According to a high recurrent rate of OKCs treated by enucleation, clinicians should give more attention to the dentate area if the enucleation is chosen as the treatment of choice.

Potential pitfalls in diagnostic oral pathology: a review for the general surgical pathologist

Oral developmental, reactive, benign neoplastic and malignant neoplastic conditions, many odontogenic in origin, may not be seen routinely by the general surgical pathologist and therefore may present a diagnostic dilemma. This article describes odontogenic and nonodontogenic conditions with little or no destructive potential along with the more aggressive conditions that resemble them clinically and histologically. The importance of clinical and radiographic correlation as an adjunct to tissue diagnosis is highlighted. Additionally, a brief summary of odontogenesis is presented with attention given to odontogenic embryologic remnants and the developmental and pathologic processes that may arise from them.

Odontogenic cysts: a clinical study of 90 cases

The maxillofacial region is affected by a greater number of cysts than any other part of the body. In this study, 90 odontogenic cysts were collected from 90 patients over a five-year period. Patients with radicular cysts, dentigerous cysts and odontogenic keratocysts were further analyzed with regard to age, sex and anatomical distribution. Using the histological classification of the World Health Organization, 53 cases (59%) were classified as radicular cysts, 24 (27%) as keratocysts and 13 (14%) as dentigerous cysts. Radicular cysts occurred most frequently in the anterior region of the maxilla, odontogenic keratocysts in the ramus and angular region of the mandible, and dentigerous cysts in the mandible. No recurrences were observed during the limited follow-up period.

Nevoid basal cell carcinoma syndrome: a retrospective analysis of 33 affected Korean individuals

This article describes a pooled analysis of Korean individuals with nevoid basal cell carcinoma syndrome (NBCCS). The data upon which this review is based has been retrieved from published case reports in Korean dental and medical literature between the years 1981 to 2002. We found 33 subjects who met the diagnostic criteria for NBCCS. Relative frequencies of associated complications are presented and compared with those of the English literature. Odontogenic keratocyst (OKC) and palmar and/or plantar pits, and hypertelorism were the most frequently observed anomalies. OKCs are often the first signs of NBCCS and can be detected in patients younger than 20 years of age. However, the incidence and clinical manifestations of NBCCS in Korean individuals were found to be rather different from those of other countries. The relatively low frequency of basal cell carcinomas and falx calcification among the major criteria were two major differences. The frequencies of the minor criteria concur in general with the ranges given by some others. It is concluded that these differences may be attributed to genetic and geographic differences.

Molecular Analysis to Demonstrate That Odontogenic Keratocysts Are Neoplastic

Context.—Odontogenic keratocysts (OKCs) are unique odontogenic lesions that have the potential to behave aggressively, that can recur, and that can be associated with the nevoid basal cell carcinoma syndrome. Whether they are developmental or neoplastic continues to be debated.

Objectives.—To identify loss of heterozygosity of tumor suppressor genes in OKCs and to suggest a pathogenetic origin for these lesions.

Design.—We examined 10 OKCs for loss of heterozygosity of tumor suppressor genes, using a microdissection and semiquantitative genotyping analysis. The genes analyzed included 10 common tumor suppressor genes, as well as the PTCH gene, which is mutated in nevoid basal cell carcinoma syndrome.

Results.—Loss of heterozygosity was seen in 7 of 10 cases, with a frequency between 11% and 80% of the genes studied. The genes that exhibited the most frequent allelic losses were p16, p53, PTCH, and MCC (75%, 66%, 60%, and 60%, respectively). Daughter cysts were associated with a higher frequency of allelic loss (P = .02), but epithelial budding was not.

Conclusions.—Our study indicates that a significant number of OKCs show clonal loss of heterozygosity of common tumor suppressor genes. The finding of clonal deletion mutations of genomic DNA in these cysts supports the hypothesis that they are neoplastic rather than developmental in origin.

Maxillary unicystic ameloblastoma

The authors present the case of a 17-year-old White male patient complaining of enlargement in the gingival region and the fundus of the left maxillary anterior vestibular sulcus. The clinicopathological diagnosis was plexiform unicystic ameloblastoma. With this report, the authors illustrate the importance and complexity of a differential diagnosis of lesions with a cystic aspect in the anterior region of the maxilla, among them inflammatory radicular cysts, odontogenic keratocysts, adenomatoid odontogenic and unicystic ameloblastoma.