Odontogenic keratocysts: clinicopathologic study of 87 cases

Management of multiple odontogenic keratocysts associated with nevoid basal cell carcinoma syndrome: a case report of 11-year follow-up

Multiple odontogenic keratocysts (OKC) are a distinguishing feature of nevoid basal cell carcinoma syndrome (NBCCS). Owing to the high recurrence rate of syndromes associated OKCs, complete surgical resection is generally recommended as a definitive treatment. Herein, we report the management of multiple OKCs with marsupialization followed by excision with peripheral ostectomy in an NBCCS patient. We then discuss lesion progression over 11 years of annual follow-ups.

Hybrid Ameloblastoma Arising from a Treated Odontogenic Keratocyst of the Mandible: A Case Report With Literature Review

Odontogenic Keratocyst (OKC) is an odontogenic cyst of developmental origin arising from remnants of the dental lamina. Malignant or benign transformations though rare have been noticed from their epithelium. Ameloblastomatous transformation from an OKC is extremely rare with such lesions being referred to as combined/"hybrid" odontogenic lesions. In this article, we present an intriguing case of a 60-year-old male who was operated on for OKC of the anterior mandible 3 years before, who came back with a complaint of swelling over the same site. Incisional biopsy revealed the acanthomatous type of ameloblastoma for which segmental resection with immediate reconstruction using recon plate was done. Excision biopsy revealed a plexiform variant as well, thus exhibiting a hybrid pattern. Surgeons should be aware of this hybrid presentation of ameloblastoma arising from the epithelium of OKC as the acanthomatous subtype is known for its notorious genetic behavior leading to recurrence and aggressive nature of this tumor.

Dystrophic calcification and respiratory metaplasia in the epithelial lining of odontogenic cysts: a study of 362 odontogenic cysts in a Brazilian population and literature review

PURPOSE

Main study: undertake a histological study of odontogenic cysts (OC) to determine the prevalence of dystrophic calcification and metaplasia to respiratory epithelium on a Brazilian population.

LITERATURE REVIEW

to review the literature for studies that investigated the prevalence of respiratory metaplasia and dystrophic calcification on OC.

METHODS

Main study: a retrospective histopathological evaluation was made of the archives from a pathology laboratory. A total of 362 cases diagnosed as OC were identified; they were analyzed by two expert observers to determine the presence of dystrophic calcification and respiratory metaplasia. The association with sex, age and anatomic location was performed through statistical analysis.

LITERATURE REVIEW

a critical literature review was undertaken. Two main electronic databases (PubMed and LILACS) were searched. Retrospective studies of histological evaluation that determined the prevalence of epithelial metaplasia and dystrophic calcification on OC, with at least 10 cases, were included; their findings were summarized and discussed.

RESULTS

Main study: the histological evaluation of OC revealed the presence of respiratory epithelium in 25 cases (6.9%) and dystrophic calcification in 24 cases (6.6%). Positive association was found to dystrophic calcification on residual cyst and age; respiratory metaplasia on OC and sex; respiratory metaplasia on residual cyst and gnatic bone; respiratory metaplasia in OC and gnatic bone; dystrophic calcification in OC and anatomic site of mandible.

LITERATURE REVIEW

eleven studies were included in the literature review, and respiratory metaplasia ranged from 0.0% to 19.2% while dystrophic calcification ranged from 2.5% to 40.5%.

CONCLUSIONS

the histological evaluation of this study found 6.9% of prevalence of respiratory metaplasia and 6.6% of dystrophic calcification, which is in accordance with the literature reviewed. Therefore, these phenomena must be taken into account in routine diagnosis services.

The presentation of odontogenic keratocysts in the jaws with an emphasis on the tooth-bearing area: a systematic review and meta-analysis

PURPOSE

This study was conducted in order to gain insight in the actual ratio of odontogenic keratocysts occurring in the tooth-bearing area as compared to the posterior region of the jaws in order to come up with reliable data to base upon a rational treatment policy.

METHODS

We searched MEDLINE, Web of Science, Scopus, and Cochrane databases for studies reporting on the location of mandibular and maxillary odontogenic keratocysts. All records were independently assessed and a meta-analysis was performed. Risk difference with a confidence interval of 95% of having the lesion in the posterior region versus the tooth-bearing area was the effect measure. P value for the summary effect of < 0.05 was considered statistically significant.

RESULTS

The 2615 records retrieved were reduced to 34 studies to be qualitatively/quantitatively assessed. The pooled values showed that the difference in the clinical risk of having keratocysts in the posterior region of the mandible and in the tooth-bearing area of the maxilla is 21 and 43%, respectively (P < 0.02 and P < 0.00001).

CONCLUSIONS

A substantial amount of keratocysts occur in the tooth-bearing area of the jaws, requiring attention.

The Inflammatory Radicular Cysts Have Higher Concentration of TNF-α in Comparison to Odontogenic Keratocysts (Odontogenic Tumour)

TNF-α is a pleiotropic cytokine that is considered as a primary modifier of inflammatory and immune reaction in response to various inflammatory diseases and tumour. We investigated levels of TNF-α in 43 radicular cysts and 15 odontogenic keratocysts, obtained from patients undergoing surgery, under local anaesthesia, and after aspiration of cystic fluid from non-ruptured cysts. TNF-α is elevated in both cysts’ fluid, but higher values were found in radicular cysts in comparison to keratocysts. The significantly higher concentration of TNF-α was associated with smaller radicular cysts, higher protein concentration, higher presence of inflammatory cells in peri cystic tissues, and the degree of vascularisation and cysts wall thickness (Mann-Whitney U-test, p<0.05). No correlation was found based on these parameters in odontogenic keratocyst, but all cysts have detectable concentrations of TNF-α. We here for the first time present that a difference in the concentration of TNF-α exists between these two cystic types.

A Case of an Extensive Keratocystic Odontogenic Tumor in the Mandible Reconstructed with a Custom-Made Total Joint Prosthesis

The use of virtual surgical planning and computer-aided design/computer-aided manufacturing has previously been reported to enhance the planning for the reconstruction of mandibular continuity defects and to reduce surgical time. Reported is a case of a large keratocystic odontogenic tumor (KOT) affecting right hemimandible including the condylar neck. This case was initially reconstructed with a condyle-bearing reconstruction plate, but because of fatigue fracture 15 years later, a new reconstruction with a custom-made total joint temporomandibular prosthesis was performed.

Treatment of nevoid basal cell carcinoma syndrome: a case report

Nevoid basal cell carcinoma syndrome (NBCCS), also known as Gorlin syndrome, is characterized by various embryological deformities and carcinoma formation. It is caused by PTCHI gene mutations and is autosomal dominantly inherited. Some of the main symptoms of NBCCS are multiple basal cell carcinomas, multiple keratocystic odontogenic tumors (KCOTs) of the mandible, hyperkeratosis of the palmar and plantar, skeletal deformity, calcification of the falx cerebri, and facial defomity. Recurrent KCOT is the main symptom of NBCCS and is present in approximately 90% of patients. In NBCCS, KCOTs typically occur in multiples. KCOTs can be detected in patients under the age of 10, and new and recurring cysts develop until approximately the age of 30. The postoperation recurrence rate is approximately 60%. This case report presents a 14-year-old female patient with a chief complaint of a cyst found in the maxilla and mandible. The patient was diagnosed with NBCCS, and following treatment of marsupialization and enucleation, the clinical results were satisfactory.

Keratocystic odontogenic tumor: A biopsy service's experience with 104 solitary, multiple and recurrent lesions

Background

Keratocystic odontogenic tumor (KCOT) is a clinically significant cystic lesion of odontogenic origin. This study aimed to retrospectively review and describe the clinicopathologic features of KCOT and to objectively compare the clinical and histological features of solitary, multiple and recurrent KCOT in a Saudi Arabian population.

Material and Methods

Biopsy request forms, pathology records and archival materials (all histological slides) of 104 cases of KCOT from 75 patients were retrieved. Demographic and clinical details as well as histological evaluation were analyzed and compared between the 3 groups using chi-squared or Mann-Whitney tests of association as appropriate.

Results

Significant differences were noted in the age of presentation, location and association with impaction between multiple and solitary cases. Histologically, there was a difference in the mitotic count, presence of satellite cysts and proliferating odontogenic epithelium between solitary and multiple lesions. There was no difference between the KCOT that later recurred and solitary lesion which did not recur even when matched clinically for age, sex and location. There were differences when solitary KCOT that later recurred or recurrent KCOT were compared with multiple lesions. Multiple lesions still had more significant proliferative activity parameters than solitary recurrence-related KCOT.

Conclusions

KCOTs in Saudi Arabians are not different from those reported from other parts of the world. Clinical and histological analyses showed multiple KCOT is different from its solitary recurrent or non-recurrent counterparts and has a higher proliferative activity than both. Clinicohistologic features alone cannot wholly explain the behavior of KCOT.

Key words:Descriptive study, keratocystic odontogenic tumor, odontogenic keratocyst, solitary, multiple, recurrent.

Aggressive osseous commitment result by keratocyst odontogenic tumour: case report, radiographic and clinical standpoints

Keratocystic odontogenic tumour (KCOT) previously known as odontogenic keratocyst was recently classified as a benign lesion characterized by an infiltrating pattern, local aggressiveness with the propensity to recurrence. It is thought to arise from the dental lamina. Pain is usually not associated with KCOT until swelling occurs, and it commonly affects the posterior mandible. Multiple KCOT are associated with nevoid basal cell carcinoma syndrome. This study reports an aggressive case of KCOT with destruction of the osseous tissue of the mandible, accentuated face asymmetry, dysphagia and dysphonia. It was managed with a defined protocol which entailed diagnosis, treatment with enucleation along with peripheral ostectomy and rehabilitation. A long-term follow-up schedule was provided to the patient to observe the recurrence behaviour of this cyst. In postoperative phase, no complication was noticed regarding wound healing and recurrence.

Keratocystic odontogenic tumor: systematic review with analysis of 72 additional cases from Mumbai, India

OBJECTIVE

The aim of this systematic review was to assess the clinical and imaging findings of keratocystic odontogenic tumor (KOT). This article also attempts to determine the prevalence of KOTs and orthokeratinized odontogenic cyst (OOC) in the western Indian population and to compare demographic and radiographic findings of KOT of our cohort with that of the rest of the world.

STUDY DESIGN

Relevant publications on KOT were reviewed from the published literature from 1976 to March 2012. Data regarding the 72 additional cases from Mumbai also were analyzed.

RESULTS

Sixty-five reports were identified for this systematic review. The findings were divided into 4 global groups for analysis. The prevalence of KOT was 0.0173% and that of OOC 0.0012%. Male sex, mandible, and the unilocular variation were predominant for the additional cases.

CONCLUSIONS

The characterization of the KOT lesions was accomplished, taking into consideration the variations to the western Indian population.

Novel PTCH1 mutations in patients with keratocystic odontogenic tumors screened for nevoid basal cell carcinoma (NBCC) syndrome

Keratocystic odontogenic tumors (KCOTs) are cystic tumors that arise sporadically or associated with nevoid basal cell carcinoma syndrome (NBCCS). NBCCS is a rare autosomal dominantly inherited disease mainly characterized by multiple basal cell carcinomas, KCOTs of the jaws and a variety of other tumors. PTCH1 mutation can be found both in sporadic or NBCCS associated KCOTs. The aim of the current study was to assess whether a combined clinical and bio-molecular approach could be suitable for the detection of NBCCS among patients with a diagnosis of keratocystic odontogenic tumors (KCOTs). The authors collected keratocystic odontogenic tumors recorded in the database of the Pathology Department of the University of Modena and Reggio Emilia during the period 1991–2011. Through interviews and examinations, family pedigrees were drawn for all patients affected by these odontogenic lesions. We found out that 18 of the 70 patients with KCOTs and/or multiple basal cell carcinomas actually met the clinical criteria for the diagnosis of NBCCS. A wide inter- and intra-familial phenotypic variability was evident in the families. Ameloblastomas (AMLs) were reported in two probands that are also carriers of the PCTH1 germline mutations. Nine germline mutations in the PTCH1 gene, 5 of them novel, were evident in 14 tested probands. The clinical evaluation of the keratocystic odontogenic tumors can be used as screening for the detection of families at risk of NBCCS. Keratocystic odontogenic lesions are uncommon, and their discovery deserves the search for associated cutaneous basal cell carcinomas and other benign and malignant tumors related to NBCCS.

Conservative management of keratocystic odontogenic tumors of jaws

PURPOSE

The aim of this study was to evaluate different surgical treatment methods for keratocystic odontogenic tumors (KCOTs) and the outcome of those treatments over a 9-year period.

PATIENTS AND METHODS

A retrospective review was performed on 43 KCOTs in 39 patients. In radiographic evaluations for diagnosis, follow ups and before and after treatment, panoramic, 3D CT and MR images were used. The three groups of different surgical treatment were (1) enucleation for small unilocular lesions without certainty of histology; (2) enucleation with Carnoy's solution, for small unilocular lesions after previous histological confirmation of KOCT; (3) marsupialization followed by enucleation with Carnoy's solution implemented for large often multilocular KCOTs with intact or destruction of cortical bone without infiltration of neighbouring tissue.

RESULTS

43 KCOT cases were mostly localized in mandible (76.7%), radiologically unilocular (72%), and parakeratocysts (88.4%). Inflammation and satellite cysts (daughter cysts) were detected histopathologically in 14 (32.5%) and 7 (16.3%), respectively. Among the 43 cysts, 20 (46.5%) were associated with the impacted third molar and of 21 (48.8%) was in tooth bearing area, and 5 (11, 6%) located on edentulous areas. It was located mostly in the anterior region of maxilla (90%) and in mandibular molar and ramus (62.8%). The treatments of KCOTs were 18 (41.9%) for group 1, and 10 (23.3%) group 2, and 15 (34.8%) group 3. A statistically significant relationship was found between the radiographic appearance and treatment methods (P = 0.00). No recurrence was found on 40.54 ± 23.02 months follow up.

CONCLUSION

We concluded that successful treatment methods were enucleation and Carnoy's solution in small lesions and marsupialization in lesions that have reached a very large size, but because KCOT was observed in second decade mostly, long-term follows up are suggested.

Histopathological Features of Keratocystic Odontogenic Tumor

The aim of this study was to describe the clinicopathologic features of 177 keratocystic odontogenic tumors (KCOTs) diagnosed in a Brazilian population. A total of 177 KCOTs were reviewed and affected 158 patients with ages ranging from 5 to 79 years (mean age = 32 years) with a slight female predominance. Mandible was the most common affected site (69.3%), and a unilocular radiolucency was the most common radiographic image. Microscopically, all cases showed at least focal areas of classic KCOT, but several histological aspects were also observed, including diffuse and focal epithelial lining hyperplasia (48.6%), epithelial budding (12.4%), reactive cytological alterations (11.3%), dystrophic calcification (7.9%), daughter cysts (7.8%), odontogenic epithelial remnants (4.5%), focal areas of orthokeratinization (2.8%), and ameloblastomatous epithelium (1.7%). These variations may make KCOT diagnosis challenging in some cases, so careful full-sample analysis and knowledge of these uncommon histological features associated with KCOT are essential for correct diagnosis.

Keratocystic odontogenic tumour: systematic review

OBJECTIVES

The aim of this review is to evaluate the principal clinical and conventional radiographic features of non-syndromic keratocystic odontogenic tumour (KCOT) by systematic review (SR), and to compare the frequencies between four global groups.

METHODS

The databases searched were the PubMed interface of Medline and LILACS. Only those reports of KCOTs that occurred in a series of consecutive cases, in the reporting authors' caseload, were considered.

RESULTS

51 reports, of 49 series of cases, were included in the SR. 11 SR-included series were in languages other than English. KCOTs affected males more frequently and were three times more prevalent in the mandible. Although the mean age at first presentation was 37 years, the largest proportion of cases first presented in the third decade. The main symptom was swelling. Over a third were found incidentally. Nearly two-thirds displayed buccolingual expansion. Over a quarter of cases recurred. Only a quarter of all SR-included reported series of cases included details of at least one radiological feature. The East Asian global group presented significantly as well-defined, even corticated, multilocular radiolucencies with buccolingual expansion. The KCOTs affecting the Western global group significantly displayed an association with unerupted teeth.

CONCLUSIONS

Long-term follow-up of large series that would have revealed detailed radiographic description and long-term outcomes of non-syndromic KCOT was lacking.

Orthokeratinized odontogenic cyst: a systematic review

OBJECTIVES

The aims of the review were to evaluate the principal clinical and conventional radiographic features of orthokeratinized odontogenic cyst (OOC) by systematic review (SR), and to compare the frequency of OOC between four global groups.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS. Only those reports of OOCs that occurred in a consecutive series of OOCs in the reporting authors' caseload were considered.

RESULTS

37 reports on 36 case series were included in the SR. OOC affected males twice as frequently and the mandible almost 2.5 times as frequently. Although the mean age at first presentation was 35 years, the largest proportion of cases first presented in the third decade for the Western, East Asian and Latin American global groups. Seven reports included details of at least one clinical finding. 11 reported case series included at least 1 radiological feature. All OOCs were radiolucent, 93% were unilocular and 68% were associated with unerupted teeth. 28% of the reported case series included follow up. 4% of OCC recurred and all of these were in the Western global group.

CONCLUSIONS

Although one feature of OOCs is that they are unlikely to recur, some do. Not only is there a lack of long-term follow up of large series with long-term outcomes of OOC, but there is a paucity of clinical and radiological details of OOC at initial presentation.

Prevalence, treatment and recurrence of odontogenic keratocyst in central India

OBJECTIVE

The present study aimed to evaluate the prevalence, sex predilection and treatment modalities of OKC in Central India.

MATERIALS AND METHODS

Total 2900 patients were screened from various hospitals and centers. Age of patients and site of lesion was recorded. OKC was classified into initial, moderate and advanced depending on the radiological involvement and treatment modalities given with respect to the extent of the OKC.

RESULT

Total 49 patients were diagnosed with the presence of OKC. It was found that mostly it is common in 3rd and 4th decades, with the mean age 28 years in males and 31 years in females. The most common site of occurrence was angle of mandible and the ramus region. The treatment of OKC, on the basis of the radiographic classification, gives excellent results with minimum recurrences.

CONCLUSION

The most common age and site occurrence was relevant with that of previous studies (Browne, Br Dent J 128(5):225-231, 1970, Chen and Lin, Gaoxiong Yi Xue Ke Xue Za Zhi 2(9):601-607, 1986). This study concluded by considering multicentric incidence, prevalence of OKC in Central India, that the population should be screened for OKC. The screening should be done by clinical, radiological and histopathological. While screening all the parameters should be considered to diagnose and treat the patients for the prevention of morbidity.

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.

Odontogenic tumors in Dakahlia, Egypt: analysis of 82 cases

OBJECTIVE

This study was designed to analyze the frequency and distribution of different types of odontogenic tumors in Dakahlia, Egypt, and to compare them with various reports from other parts of the world.

STUDY DESIGN

Records of the Oral and Maxillofacial Surgery and Oral Pathology Departments, Faculty of Dentistry, Mansoura University, with histologic diagnosis of odontogenic tumors (based on the World Health Organization classification, 2005), during a 15-year period, were analyzed.

RESULTS

A total of 82 cases of odontogenic tumors were reported. Of these, (96.3%) were benign and (3.7%) were malignant. Ameloblastoma (41.5%) was the most frequent type, followed by keratocystic odontogenic tumor (19.5%), odontoma (13.4%), and odontogenic myxoma (8.5%). The mean age of the patients was 29.57 years, with a wide range (4-80 years).

CONCLUSIONS

Odontogenic tumors show a definite geographic variation. In Dakahlia, Egypt, ameloblastoma and keratocystic odontogenic tumor are the most frequent odontogenic tumors, with distinct anatomic predilections.

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.

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.

Midline maxillary odontogenic keratocyst

Odontogenic keratocysts are odontogenic cysts of the jaw, usually the mandible. We present a recurrent case in the maxilla. Immunohistochemical staining is necessary to distinguish the entity from other cystic lesions of the jaw, and aggressive surgical management is required.

Maxillary odontogenic keratocyst: a common and serious clinical misdiagnosis

BACKGROUND

The authors conducted this study to determine the most common location of odontogenic keratocysts, or OKCs, in the maxilla and the implication of this for dental practice.

METHODS

The authors reviewed all cases diagnosed as an OKC by the Oral and Maxillofacial Pathology Diagnostic Laboratory at University of Florida College of Dentistry from July 1, 1993, to June 30, 2001. They determined the location for each cyst and recorded relevant clinical information such as age and sex. In addition, the authors noted the practitioners' clinical diagnoses for the cases in the most common location in the maxilla and compared them with the final diagnosis.

RESULTS

A total of 398 OKCs occurred in 393 patients. Of the 398 cysts, 266 (66.8 percent) were in the mandible, and 132 (33.2 percent) were in the maxilla. The most common location for OKCs was the third molar and ramus area of the mandible, with 137 cysts. The canine region of the maxilla, with 54 cysts, was the second most common location. Submitting clinicians mentioned OKC as a diagnostic possibility in only 31.5 percent of the maxillary canine region cases.

CONCLUSION

The most common maxillary location for OKCs is the canine region where they commonly are mistaken for an apical inflammatory lesion or lateral periodontal cyst. Accurate diagnosis is essential for proper patient therapy and follow-up.

CLINICAL IMPLICATION

A diagnosis based solely on clinical information can be problematic. In many cases, histologic examination of surgically removed tissue is necessary to establish a definitive diagnosis. That is particularly true for cases that do not resolve when treated by conservative endodontic therapy.

Odontogenic keratocyst with dentinoid formation

Although rare, hard tissue deposits, namely dystrophic calcifications and cartilage, have been reported to occur in the connective tissue wall of the odontogenic keratocyst. However, dentinoid formation has not been previously documented. A case involving the left mandibular premolar-molar region in a 37-year-old Malay male is described here along with a brief review on the reported prevalence of hard tissue deposits in the odontogenic keratocyst. Differential diagnosis of this case from other dentinoid-forming odontogenic cysts and tumors-notably calcifying odontogenic cyst, odontoma, ameloblastic fibro-odontoma, central odontogenic fibroma and adenomatoid odontogenic tumor that may present with dentin/dentinoid formation-is discussed.

Immunohistochemical study of the orthokeratinized odontogenic cyst: a comparison with the odontogenic keratocyst

OBJECTIVE

Orthokeratinized odontogenic cyst (OOC) is a developmental cyst that occurs in the maxilla and the mandible and is defined by the World Health Organization as the uncommon orthokeratinized type of odontogenic keratocyst (OKC). However, studies have shown that OOC has peculiar clinicopathologic aspects and biologic behavior when compared with other developmental odontogenic cysts, especially OKCs. Therefore, in this study, the immunohistochemical profile of the OOC was delineated and compared with that of the OKC.

STUDY DESIGN

Twelve cases of OOC were submitted to a panel of antibodies composed of cytokeratins (10, 13, and 14) and extracellular matrix proteins: fibronectin, types I and III collagen, and tenascin. For comparative means, 12 cases of OKC also were submitted to the same panel of antibodies.

RESULTS

The results obtained showed that OOCs expressed cytokeratin 10 and showed variable expression of cytokeratins 13 and 14. Fibronectin and collagen types I and III also were expressed in OOC in a fibrillar aspect. OKC showed only the superficial keratin layer positive to cytokeratin 10 and the basal and suprabasal layers with variable expression of cytokeratin 14, and cytokeratin 13 was present in the upper epithelial layers. The extracellular matrix proteins showed a nonfibrillar expression. Tenascin was immunoexpressed only in OKC.

CONCLUSION

The immunohistochemical profile of the studied cysts clearly showed that OOC presents a well-formed cystic enveloping, whereas the OKC profile is compatible with a more aggressive biologic behavior.

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

Odontogenic keratocyst (OKC) is of particular interest because of its high recurrence rate and aggressive behavior. Two hundred fifty-six cases of OKC were reviewed for the age of the patient at diagnosis, sex of the patient, OKC location, and radiographic findings, and 132 patients with OKC were observed to estimate recurrence, which was analyzed for age, sex, location, and several histopathologic findings. OKCs occurred more frequently in men (58.6%) than in women (41.4%), and they occurred in patients within a wide age range, most commonly in patients in the third decade of life (28.9%), followed by those in the second decade (25.0%); the mean age of patients with OKC was 30.8 years. One hundred ninety-six of the 256 cases (76.5%) occurred in the mandible, and the other 60 cases (23.5%) occurred in the maxilla. The mandibular molar and the premolar areas (51.2%) were the most common sites, and the most frequent clinical manifestations at first admission were swelling, pain, or both (82.4% of total cases). Radiographic impressions included dentigerous cyst (27.3%), OKC (25.4%), primordial cyst (14.8%), ameloblastoma (11.7%), residual cyst (9.8%), and radicular cyst (3.1%). The frequency of recurrence at the follow-up examination was 58.3%. There was no significant difference in the recurrence rate on the basis of the sex of the patient. However, OKCs had a significantly higher recurrence rate in patients in the fifth decade of life than in patients in the other age groups (P = .005).Recurrence rates were significantly dependent on the sites of involvement, and OKCs in the mandibular molar region had significantly higher recurrence rates than those in other sites (P = .001). The histopathologic presence of one or more daughter cysts was significantly related to recurrence (P = .03).

Long-term follow-up on keratocysts treated according to a defined protocol

A prospective study was conducted on 82 odontogenic keratocysts (OKCs) diagnosed in 80 patients over a 25 year period. The clinical and radiographic data were correlated, which resulted in an accurate picture of the clinical presentation, relationship with teeth and incidence of lingual perforations in mandibular OKCs. In 40% of the cysts no suspicion had arisen before surgery, in 60% the diagnosis was secured before surgery. This last group of patients was treated according to a defined protocol, with the exception of the maxillary OKCs, which entailed excision of the attached, overlying mucosa and enucleation of the cyst after which the defect was treated with Carnoy's solution. The other patients underwent just enucleation of the cysts. For the first 5 years the patients were seen every year, thereafter every 2 years if possible. Recurrences (9/82) were mainly found in the patients in which the cyst had just been enucleated. Only three cysts recurred in the group treated according to the above mentioned protocol. Most recurrences presented within 5 years, but late recurrences did occur even after 25 years. The aetiology and pathogenesis of OKCs is briefly discussed in the light of the present findings. It is concluded that the suggested treatment protocol and follow-up schedule provides a safe means to manage a lesion that is known to recur and may even give rise to life threatening situations.

The odontogenic keratocyst: a 20-year clinicopathologic review

The odontogenic keratocyst (OKC) is a jaw cyst with a proclivity for local invasion and recurrence. This 20-year retrospective study was conducted to evaluate methods of treatment and recurrence rates. Forty-nine patients were identified with an average age at presentation of 39.5 years. The molar region of either the mandible or maxilla was the principal primary location; the maxillary antrum was also a common site. The majority of cysts were unilocular and associated with adjacent dentition. Initial therapy was typically enucleation with or without extraction of associated teeth; seven cases of recurrent or second primary odontogenic keratocysts required more extensive surgery. Follow-up ranged from 1 to 15 years with an average duration of 4.3 years. The overall recurrence rate was 35%, and the average time to recurrence 4 years. A recurrence rate of 60% was documented for patients with basal cell nevus syndrome or a family history thereof. Long-term follow-up is necessary following initial OKC treatment. The high rate of recurrence in patients with documented or suspected basal cell nevus syndrome suggests the need for more aggressive initial surgical management in this selected patient population.

Extensive Odontogenic Keratocysts of the Maxilla: Review of the Literature and Report of Six Cases

The clinical, radiological and histological features of six large maxillary odontogenic keratocysts are reviewed. Special treatment considerations for extensive maxillary lesions are discussed. Patient follow-up, including imaging studies, is important to allow the early detection and treatment of recurrent lesions when they are small and well localized.

Odontogenic keratocysts of the midline maxillary region

PURPOSE

This article compares the demographic features of the anterior midline maxillary odontogenic keratocyst with those in other regions.

MATERIALS AND METHODS

The data on 18 cases of anterior midline maxillary odontogenic keratocyst were reviewed.

RESULTS

Thirteen of the cases were in men (72.2%), and 16 of the patients (88.9%) were past the age of 60 years. The mean age of the patients was 69.9 years, which is much higher than for odontogenic keratocysts in other locations. The most common clinical diagnoses were periapical cyst and nasopalatine duct cyst.

CONCLUSION

It is important to include odontogenic keratocyst in the differential diagnosis of anterior midline maxillary radiolucencies, especially when they occur in older individuals.

Increased attenuation in odontogenic keratocysts with computed tomography: a new finding

An increased attenuation area (IAA) is sometimes seen in the cystic cavity of odontogenic keratocysts (OKCs) on CT scans. The significance of IAA was compared radiologically and histologically in 26 cysts in which a provisional diagnosis of OKC had been made. First, the presence of IAA in the cystic cavity was assessed. Then, relationship between the presence of IAA and data obtained from the cysts, including the CT and histological findings and the visual appearance of the cyst contents, was evaluated. An IAA was frequently seen in large multilocular cysts. There was no relationship between the presence of IAA and aggressive features of the cyst on CT or the cyst contents. Histologically, subepithelial inflammation was often observed in the cysts with IAA. In order to ascertain whether the IAA was due to the keratin mass, a CT scan of a bundle of hair in a water bath was performed and shown to have a similar density. Our study demonstrated that IAA in cystic cavities results from desquamated keratin. Since this seems to occur in long-standing or inflamed multilocular OKCs, it could be used as a significant finding in the diagnosis of OKC.

'Combined ameloblastoma and odontogenic keratocyst' or 'keratinising ameloblastoma'

Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.

Odontogenic keratocysts: a clinical and histologic comparison of the parakeratin and orthokeratin variants

Four hundred forty-nine cases of odontogenic keratocyst (OKC) were separated into three histologic categories: parakeratinized, orthokeratinized, or a combination of the two types. Demographic and clinical data, such as anatomic location and recurrence, were obtained from the biopsy forms. Results showed that 86.2% of the 449 cases were parakeratinized, 12.2% were orthokeratinized, and 1.6% had features of both orthokeratin and parakeratin. There were no statistically significant differences between orthokeratinized and parakeratinized OKCs when age, race, sex, presenting symptoms, and the clinical impression were compared. The orthokeratinized OKC was more often associated with an impacted tooth (75.7%), as compared with 47.8% for the parakeratinized OKC (P = .001). Parakeratinized OKCs recurred in at least 42.6% of the cases, compared with only 2.2% for orthokeratinized OKCs. This study emphasizes the importance of distinguishing between the parakeratin and orthokeratin variants of OKC. In addition, data are presented that show the need for longer follow-up than previously documented.

Treatment of a large odontogenic keratocyst using the Brosch procedure

The modified Brosch procedure has been described. It represents a reasonable alternative to resection or marsupialization when treating large OKC that occupy the molar, angle, and ramus regions of the mandible. Extraction of teeth affected by the lesion as well as generous removal of partially eroded bone and overlying soft tissues may contribute to lower recurrence rates. Cryosurgical or mechanical treatment of the bony cavity, which is well visualized using this technique, may also lead to improved long-term results. Treatment must be followed by continued, careful observation of the patient.

Gorlin's syndrome with associated odontogenic cysts

Multiple maxillary and mandibular cysts are principle features of basal cell nevus syndrome (Gorlin-Goltz). We present cases from an affected family in which magnetic resonance imaging (MRI) was helpful in evaluation of the cystic lesions. A middle ear anomaly was identified which may represent an additional abnormality associated with the syndrome.