Central odontogenic fibroma (COF) is an uncommon slow growing benign neoplasm that is derived from the mesenchymal tissue. Differential diagnoses include fibrous dysplasia, calcifying odontogenic cyst, and central ossifying fibroma. Clinically, the lesion shows expansion of cortical bone. Radiologically, unilocular or multilocular lesion with well-defined borders is found. Histologically, fibroblastic tissues with bundle of collagens including inactive odontogenic epithelium can be observed. In this case report, a 45-year-old male with central odontogenic fibroma of the maxilla is examined. The lesion was surgically removed without any postoperative complications. In order to diagnose the disease properly, histopathologic analysis was performed.

Orthokeratienized odontogenic cyst (OOC) is a comparatively unusual developmental odontogenic cyst arising from odontogenic epithelium. Recurrence has rarely been noted, and has been reported in less than 2% of cases. Epidermoid cyst (EDC) is a benign cystic lesion, which is lined by stratified squamous epithelium and includes keratin debris. They can present anywhere in the body but are rare in the head and neck areas. In this report, we present an uncommon case of simultaneous occurrence of OOC in mandible and EDC around the areas of both ears in a patient who has no history of genetic syndrome.

Dentigerous cyst is considered one of the representative cystic lesions, which accounts for approximately 15%-30% of the odontogenic cysts. Although its recurrence rate is low, a small proportion of dentigerous cysts converted into ameloblastomas, squamous cell carcinomas, and mucoepidermoid carcinomas. Here we present an uncommon case characterized by histopathological transformation from a dentigerous cyst to an ameloblastoma, and further investigate the factors contributing to its conversion.

The purpose of this study is to research about the construction of Chiseong around the Heunginjimun Gate area in the 18th century. the conclusions derived from the historical evidence of the number, location, size, and form, and construction method of Chiseong was as follows. First, the Chiseong(Square-shaped lookout) of Hanyangdoseong was built in the 29th year of King Yeongjo(1753) and can be found in the national record. Five sites of the Chiseong are currently identified. It is assumed that the Foru was installed on top of some of the Chiseongs. Second, Chiseong was destroyed sequentially in the first half of the 20th century. Third, Chiseong is a rectangular in shape and six are constructed. Fourth, Sixth Chiseong could figure out through Hengryeopungsokdo, the drawing of Jeong Seon.

Central odontogenic fibroma(COF) is a very rare benign tumor that accounts for 0.1-1.5% of all odontogenic tumors. Most COF develop in the molar-premolar region in the mandible and anterior to the first molar in the maxilla. Radiographically, the lesions appear as a unilocular or multilocular radiolucent image. Some maxillary lesions have cleft like depression in the palatal mucosa are found. This report presents a COF with external root resorption and palatal soft tissue depression on CBCT images. A 27-year-old man referred for evaluation of unilocular radiolucent lesion with external root resorption in the right anterior maxillary region. On clinical examination, the right anterior maxillary teeth responded positive to the cold stimulus and its response to the vitality test remained within the normal range. On radiographic examination, osteolytic lesion with external root resorption and palatal mucosa depression as a radiolucent shadow. After excisional biopsy, the lesion was diagnosed as COF in histopathologic examination. There was no recurrence at a follow-up 10 months.

Odontogenic keratocyst (OKC), also known as keratocystic odontogenic tumor, is a distinct clinicopathologic lesion that can be clearly identified by histologic examination. Clinically, OKC is characterized by a high recurrence rate. This report describes a rare case of OKC with mural calcification in the maxilla of a 47-year-old male patient. Orthopantomography and Cone Beam Computed Tomography showed full opacification with calcification and lateral wall resorption in the left maxillary sinus, destroying the sinus floor. Hard tissue deposits have rarely been reported in the connective tissue walls of OKC. The importance of calcified material formation to the biological behavior of OKCs is unclear. Although its prognostic value has not been studied, the presence of calcification materials does not appear to increase the risk of recurrence. Study of a number of samples would be needed to determine the nature of the correlation between the presence of calcified materials and recurrence.

Odontogenic keratocyst (OKC) is aggressive compared to other odontogenic cysts, but its malignant transformation is extremely rare. Odontogenic carcinoma may arise from an odontogenic cyst such as OKC. Here in, we introduce a case of odontogenic carcinoma assumed to have arisen from a preexisting OKC. Abnormal clinical and radiologic features seen in a previous or existing cyst may be warning signs of malignant transformation.

The myxoma(odontogenic myxoma, myxofibroma) of the jaws is a benign, usually slow-growing infiltrative tumor of connectice tissue. This article describes a case history of the treatment of recurred odontogenic myxofibroma in the maxilla and further discusses the appropriate management of such cases with reference to the literature review. A 55-year-old male patient presented with a gingival swelling in the right side of maxilla. He had history of second time recurred disease. Microscopically, a high cellularity fibrous tumor with fibroblastic cells was observed. Tumor cells were composed of stellate and spindle shaped fibroblasts. Islands of odontogenic epithelium were seen in the specimen. The final diagnosis was made with odontogenic myxofibroma in consideration of twice-time recurrences and histological characteristics. Because of the high likelihood of recurrence, an accurate differential diagnosis of pathology at the time of initial visit is very important in determining treatment options, and immunohistochemical tests may be helpful. Also close following up is required.(155 words)

Brain abscesses caused by odontogenic infection are a rare and life-threatening condition. When dental patients show neurological symptoms such as decreased consciousness, a brain abscess should be considered as a possible diagnosis. We reported that a 65-year-old man visited the emergency room because of left facial edema, high fever, limitation of mouth opening and decreased consciousness. CT, bone scan, and microbiologic examination revealed that the brain abscess originated from left mandibular osteomyelitis with an apical lesion in tooth #36. It was hard to diagnose the location of odontogenic infection. Because there were no evidence of submandibular abscess which is a common path of mandibular posterior infection, early diagnosis was difficult. MRI and radiographs such as facial CT and brain CT revealed procedure that inflammatory findings progressed through the coronoid process, the temporal space, into the subdural space. We compared the present case to previous cases, articles published after the year 2000 in Korea and abroad were investigated. The patient was treated successfully with extraction of causative teeth, drainage surgery, intravenous antibiotics by collaboration between the department of oral maxillofacial surgery and neurosurgery. It is difficult to diagnose brain abscess because central nervous system can be infected by various pathway. As shown in this case, patients with a brain abscess caused by a dental infection should be diagnosed and treated with a multidisciplinary approach.

Squamous odontogenic tumor (SOT) is a relatively rare, benign, small (rarely > 1.5 cm in diameter), but locally infiltrative and occasionally aggressive odontogenic epithelial lesion that appears to have harmatomous and neoplastic characteristics [1]. SOT is often asymptomatic, although it can present with mildly painful gingival swelling or tooth mobility. Radiographically, SOT is usually visualized as an irregularly or triangularly shaped unilocular radiolucency associated with the lateral roots of teeth. We report a case of the squamous odontogenic tumor occurring in a 60-year-old female in the right posterior maxilla with unusual radiographic and clinical appearances.

Clear cell odontogenic carcinoma (CCOC) is an extremely rare odontogenic neoplasm; Only a few cases have been reported in the English literatures. It displays a propensity for the mandible, most commonly presenting in the fifth to seventh decades, with a female predilection. The clinical and radiological manifestations are multiple and the diagnosis is histological. Histological feature is of large islands and strands of uniform cells with round or ovoid nuclei and clear cytoplasm. Clinically, painless swelling is the most common symptom, followed by pain, teeth mobility, and paresthesia. CCOC has a good prognosis after surgery. This case report presents the histopathological and clinical features of CCOC excised from the mandible.

Calcifying Epithelial OdontogenicTumor(CEOT), also known as Pindborg tumor is a rare lesion comprising about 1% of all odontogenic tumors mostly rising in the posterior of the mandible. It generally occurs in patients between 30-60 years old. This paper describes a case of CEOT in a 17 year-old female affecting the right mandible. Histopathologic findings showed sheets of polygonal tumor cells and pools of amorphous, eosinophilic amyloids with calcifications. 1 year after resection of the tumor, no clinical and radiographic signs of recurrence were observed.

Odontogenic keratocyst (OKC), also known as keratocystic odontogenic tumor (KCOT), is an emerging odontogenic tumor originating from the dental lamina. It is an aggressive lesion with a squamous epithelium and a recurrence rate of 15-35%.1 Radiologically, there is a clear, smooth, or shell-like border showing a unilocular or multifocal, polycystic radiographic picture. Hard tissue formation in OKC is a very rare phenomenon and occurs in the form of dystrophic calcification, cartilaginous tissue or dentinoid.2 In this article, we report the case of OKC with calcification. OKC with radiopaque lesion is very rare, these are considered as dystrophic calcification, dentinoid formation, ossification. The incidence of dystrophic calcification in recurrent OKC is low, so it can be inferred that the recurrence rate of OKC with dystrophic calcification is lower than that of conventional OKC.

Dentigerous cysts, the most commonly occurring developmental cysts of the jaw, develop in association with impacted teeth. Most dentigerous cysts are solitary. Multiple dentigerous cysts are rare and generally occur in association with a developmental syndrome or systemic disease, such as mucopolysaccharidosis and cleidocranial dysplasia. However, in the absence of a syndrome, occurrence of multiple dentigerous cysts is rare. Development of multiple dentigerous cysts on first molars extremely rare. The purpose of this paper was to report on a nonsyndromic, 8-year-old boy who presented multiple dentigerous cysts on first molars.

Central odontogenic fibroma(COF) is an extremely rare benign tumor that accounts for 0.1% of all odontogenic tumor. COF is regarded by the World Health Organization(WHO) as a benign odontogenic neoplasm derived from mesenchymal odontogenic tissue. The lesion occurs most commonly in the mandible and patients ranging in age from11 to 80years with mean age of 34years. In this article, we report two case of COF. Case I was associated odontoma and impacted tooth. Odontoma and impacted tooth was removal under general anesthesia. After microscopic examination, finally we diagnosis this lesion as COF. Patients of case II showed radiolucent lesion at the mandible. Lesion was enucleated under general anesthesia. After microscopic examination, finally we diagnosis this lesion as COF. The patients which we presented did not complain any specific complications, showed good prognosis.

Primary intraosseous odontogenic carcinoma (PIOC) is a carcinoma arising within the jaws, putatively developing from remnants of odontogenic epithelium. We describe a case of PIOC arising from odontogenic cyst affecting the left posterior mandible of 72-year-old Korean man. Clinical examination showed a symptom-free hard mass. There was no evidence of ulceration, and there was no pain or bleeding. The overlying mucosa was intact and no regional lymph nodes were palpable. Clinical and radiological studies for other distant primary sites were negative. Radiographically, the tumor showed multilocular radiolucency with a noncorticated, ill defined border surrounding an impacted third molar tooth. Histology exhibited sheets or islands of nonkeratinizing malignant epithelial cells with minimal clear cell component in continuity with begin or dysplastic cyst lining epithelium. Immunostaining for PCNA and p53 protein showed a higher percentage of positive cells and more intense staining in the carcinomatous tissues than in the benign and dysplastic lesions.

The dentigerous cyst is defined as a cyst that originates by the separation of the follicle from around the crown of an unerupted tooth. This is the most common type of developmental odontogenic cyst, making up about 20% of all epithelium-lined cysts of the jaws. Large dentigerous cysts are uncommon, but some cases are large cysts. The usual treatment for a dentigerous cyst is careful enucleation of the cyst together with removal of the unerupted tooth. Large dentigerous cysts also may be treated by decompression. This permits decompression of the cyst, with a resulting reduction in the size of the bone defect. The cyst can then be enucleated at a later date with a less extensive surgical procedure and important structures such as teeth and the inferior alveolar nerve can be preserved. These cases are large dentigerous cysts treated by decompression. Less extensive surgical procedures were used and some teeth were preserved.

A nineteen years old male patient showed a cystic lesion in left maxillary canine to premolar area (#23-#25). This lesion was asymptomatic, and found during his routine radiological check in local clinic. In the radiological observation the cystic lesion showed round radiolucent image containing many calcified bodies which were usually small but irregular in shape, expanding tumorously and resulted in the displacement of canine and second premolar in the absence of first premolar. The lesion was surgically enucleated, and a cystic fibrous tissue containing abnormal teeth was removed and examined pathologically. With the histological observation of tumorous odontogenic epithelium including many ghost cells, which were closely associated with abortive teeth, the lesion was finally diagnosed as CCOT associated with complex odontoma. The ghost cells of CCOT was strongly positive for β-catenin, GADD45, and LC3, and slightly positive for MMP-9, while they were rarely positive for BCL2, Wnt1, HSP-70, and p38. Therefore, it was presumed that the ghost cells of CCOT might undergo dormant cell state through altered cytodifferentiation stimulated by severe growth arrest, DNA damage signaling, and abundant autophage formation.

The aim of this study was to present the clinical, radiological, and histopathological findings of 20 new Korean GOC cases with a brief literature review. The mean age of 20 GOC patients was 43.5 years (range, 29-73 years) with a strong predilection for male (male-to-female ratio, 4:1). Nine cases were located in the maxilla and 11 cases in the mandible. Eight cases involved the anterior areas of the jaws and 12 cases were located in the posterior area. Most of the cases (16/20, 80.0%) showed a well-defined unilocular radiolucency and some showed cortical perforation (55.6%) and bony expansion (72.2%) in computed tomography. The most common histopathological feature was eosinophilic cuboidal cells (100%), followed by clear cells (95.0%), mucous cells (85.0%), variations in thickness (85.0%), and intraepithelial microcysts (80.0%). All cases were surgically treated by enucleation and no recurrences were found in routine follow-up.

Odontogenic cyst and odontogenic tumor shares developmental source. However, they have different histopathologic features, and they are classified respectively. Odontogenic cyst and tumor can share same physical region. It is called a hybrid lesion, a lesion showing the combined histopathological characteristics of two or more previously recognized odontogenic tumor and/or cysts of different categories. In this study, a hybrid lesion was researched. 61-year old man was referred to our department with a multilocular radiolucency in right mandibular angle. Incisional biopsy was carried out, and the patient was diagnosed with ameloblastoma. Odontogenic keratocyst was found with the tumor, and it was thought to be evolved via neoplastic transformation from lining epithelium of the keratocyst. After reviewing studies reporting hybrid lesions from odontogenic cyst and tumor, formation of a hybrid lesion was most frequent from a dentigerous cyst and an adenomatoid odontogenic tumor. A hybrid lesion commonly lead to misdiagnosis, and the prognosis is not always transparent. The close relationship between the odontogenic cyst and tumor has to be kept in mind in the diagnosis and treatment of the lesions in maxillofacial area.