It is well known that lymph node metastasis is a major prognostic factor in patients with oral squamous cell carcinoma (OSCC). 30-40% of patients with OSCC have already undergone regional metastasis at diagnosis. The survival rate of patients with metastasis is reduced by more than 50%. Therefore, prevention and early detection of metastasis are very important to increase the survival rate of patients. Many investigators have studied the molecular mechanism of metastasis and tried to develop the molecules to inhibit any step of metastatic cascade. Among those molecules, an interest in the metastasis suppressor gene has been increasing. Expression of metastasis suppressor KiSS-1 has shown to be significantly related to poor clinical outcome and worse survival rate of patient in various malignancies of different organs. In addition, our previous study in OSCC also revealed that downregulation of KiSS-1 expression correlated with the presence of cervical lymph node metastasis, one part of tumor progression. Therefore, further investigation was needed to identify the molecular function of KiSS-1 using OSCC cell line and to evaluate the possibility of KiSS-1 as a new therapeutic target.

Human DEK gene on chromosome 6p encodes a 43kD nuclear phospoprotein that was originally identified as part of a fusion protein found in a subset of acute myeloid leukemia carrying a t(6;9) translocation. Although DEK upregulation has been described in a number of human malignancies and was significantly associated with high histologic grade, lymph node metastasis and/or advanced clinical stage, no previous report has evaluated the expression of DEK protein and its clinical significance in oral squamous cell carcinoma (OSCC). Our aims were to determine DEK expression in tissue samples of normal oral mucosa and OSCC by immunohistochemistry, to analyze the correlation between DEK expression and clinicopathological parameters, and to evaluate the value of DEK as a prognostic marker for patient’s survival. Ten normal oral mucosa, 10 epithelial dysplasia, and 60 OSCC samples were studied by immunohistochemistry. DEK expression tended to increase through the full thickness of epithelium in the dysplastic mucosa when compared with those in normal oral mucosa. High expression of DEK protein (score ≥ 2) was found in 68.3% of OSCC cases. Statistical analysis revealed that DEK overexpression in OSCC was positively correlated with high histologic grade (p=0.001), lymph node metastasis (p=0.003), and advanced clinical stage (p=0.039). In the Kaplan-Meier survival analysis, DEK overexpression was significantly associated with decreased overall survival in patients with OSCC (p=0.019). Our results suggest that DEK overexpression may be a reliable marker to predict the clinical outcome in OSCC.

Fibromatoses are benign fibroblastic proliferation, which forms infiltrating tumor-like mass. Their histologic features cannot reflect the biologic behavior; local recurrence and aggressive infiltration to the adjacent tissue make fibromatoses intermediate tumor, between benign and malignant. Infantile fibromatosis consists of desmoid-type tumor and lipofibromatosis, and mainly affects children under age of 10. While desmoid-type tumor is characterized by elongated mature fibroblastic proliferation, the fibroblasts in lipofibromatosis look more primitive and accompany adipocytes. Here, we report a case of infantile fibromatosis of 4 month old boy involving the tongue.

Lysyl oxidase (LOX) family, the copper dependent amine oxidase, oxidizes lysine residues in extracellular collagen and elastin. LOX increases the strength of the extracellular matrix and plays an important role in tumor development and metastasis. It has been reported that increased LOX protein and RNA are found in head and neck squamous cell carcinoma. Moreover some studies regarded LOX as a prognostic marker of oral and oropharyngeal squamous cell carcinoma. However there has not been any report on LOX expression of salivary gland tumors. Here, we investigated LOX expression in mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC) of salivary gland and compare it to those of pleomorphic adenoma (PA). We evaluated LOX expression in eighteen MEC, eighteen ACC and twenty PA cases by immunohistochemical examination. Whereas PA showed relatively low density of LOX expression, ACC revealed more cases that showing high staining intensities for LOX. Significantly increased LOX expression was found in the cases of ACC when compared to those of PA (P = 0.010).

Clear cell odontogenic carcinoma (CCOC) is a very rare malignant neoplasm of jaw, with a significant clear cell component. It is nearly three times as common in the mandible with distinct female predominance. Past, identified as locally invasive tumor, CCOC is now considered to be malignant neoplasm, showing distant and regional lymph node metastasis. CCOC is histopathologically characterized by large glycogen-rich clear cells, often intermixed with eosinophilic cells. When diagnosing CCOC, ruling out salivary gland tumors, such as mucoepidermoid carcinoma or clear cell adenocarcinoma is important because they have overlapping histologic features with CCOC. Here in, we report a case of CCOC involving the right maxillary sinus of a 72-year-old female.

Neurotized melanocytic nevus (NMN) is categorized into intradermal/intramucosal type of acquired melanocytic nevus. In contrast to typical intramucosal nevus which has relatively distinct histological features, the diagnosis of NMN requires more attention due to its mimicry of benign neural tumors such as neurofibroma. The majority of lesional cells, NMN cells, showed a spindle cell morphology and abundant, eosinophilic cytoplasm which were positive for S-100, vimentin, and collagen type IV. Positive reaction for MART-1 was detected in the NMN cells as well as in the epithelioid nevus cells beneath the epithelium. Neurofibroma exhibited diffuse positivity for S-100, vimentin, CD34 and collagen type IV, but never expressed MART-1. Toluidine blue stained the numerous mast cells scattered in the lesion of neurofibroma, compared to the relatively minor detection of mast cells in NMN. Therefore, MART-1 is a useful marker in differentiating NMN from neurofibroma.

Oral squamous papilloma (OSP) is a common benign lesion of the oral mucosa that is induced by the human papillomavirus. To investigate the clinicopathological characteristics of OSP, we selected 135 patients diagnosed at the Seoul National University Dental Hospital. OSPs occurring in Koreans had a slight female predilection, with the male to female ratio being 1:1.6. The age ranged from 4 to 80 years old (average age: 47 years). The most frequent location was the soft palate (43.7%), followed by the tongue and gingiva. 11.1% of all patients presented with pain. There have been no reported cases of recurrence. On microscopic examination, two‐thirds of the lesions were parakeratinized, with almost all cases (99%) containing the koilocytes. In conclusion, there were no significant differences between the clinicopathological features of OSP in Korean and findings from previous studies

Sialolithiasis consists of calcified structures in either the salivary gland or ductal system and alteration of salivary gland parenchyma. To investigate the clinicopathological features of sialolithiasis in Korean patients, we selected 60 patients with sialolithiasis diagnosed at the Seoul National University Dental Hospital. Their clinical records and radiographs were reviewed with the analysis of available histologic data from 32 cases. The male to female ratio was 1.1:1. Sialolithiasis is most common between the ages of 20 and 60 years and occurred most frequently in the submandibular gland (97%). Upon microscopic examination, most lesions showed moderate-to-severe inflammatory infiltration and parenchymal changes such as ductal metaplasia, acinar necrosis and fibrosis. Consequently, Korean patients exhibited clinicopathological features similar to those previously reported.

Both synovial cysts and synovial chondromatoses originate from synovial tissue, and only one case has been reported to occur simultaneously in a patient. Our patient presented with a swelling of the right preauricular area and pain on opening the mouth. Magnetic resonance images demonstrated two cystic structures in the superficial lobe of right parotid gland. Under the clinical impression of a cyst in the salivary gland, an enucleation was performed. However, the final diagnosis based on microscopic examination was a synovial cyst associated with the right temporomandibular joint and a synovial chondromatosis arising within the cystic wall. Awareness of this combined lesion will help make a diagnosis and establish a proper treatment plan.

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. It is biphasic and is characterized by an admixture of epithelial and spindle-shaped myoepithelial cells in a variable background stroma. Epithelial-myoepithelial carcinoma (EMC) is a malignant biphasic salivary gland tumor typically composed of clear myoepithelial cells that surround epithelial-lined ducts resembling intercalated ducts. The differential diagnosis between the two tumor may be occasionally encountered because of the shared histophatologic feature. And then, it would be more reliable to differentiate the tumors based on biological behavior such as the expression of distinct intermediate filaments such as cytokeratin, invasiveness- related molecules, and the growth factor receptor to aberrantly facilitate the tumor growth, and the growth fraction of tumors. Therefore, from the 10 cases of PA and 6 cases of EMC, we immunohistochemically examined the differential expression of the cytokine 7 and 14, matrix metalloproteinase-9, C-KIT, and Ki-67 between the two tumor. At the results, there were significant differences of CK7 expression in non-luminal cells (P = 0.000) and CK14 expression in luminal and non-luminal cells of the both tumors (P = 0.025 and P = 0.000, respectively). In the comparison of the biologic behavior, a significantly increased expression of MMP-9, C-KIT and Ki-67 was found in the cases of EMC when compared to those of PA (P = 0.043, P = 0.011, and P = 0.000, respectively). In conclusion, the differences of CK expression in luminal and non-luminal cells between PA and EMC seem to reflect the difference of the origin and the level of the maturation of the tumor cell. Increased expression of MMP-9, C-KIT, and Ki-67 in EMC may represent more aggressive biologic behavior of the tumor compared with benign salivary tumor such as PA. Our results may be helpful to understand the histiogenesis of the two tumors and the difference of biologic behavior and to differentiate them when the limited specimen was submitted. Further study of many more cases of EMC is needed to validate the usefulness of these molecules as the diagnostic aid.

Desmoplastic ameloblastoma (DA) and Ameloblastic fibroma (AF) show common histopathologic features such as enamel organ like epithelial islands or cords on the background of abundant fibrous stroma. Despite their similar histopathologic features, it was reported that they have different pathogenesis and clinical behavior. The purpose of this study was to rev iew clinicopathologic features of DA and AF among Korean subjects. 7 cases of DA and 4 cases of AF were retrieved from the files of Seoul National University Dental Hospital (SNUDH), and their clinical features, radiographic findings, and histopathologic features were reviewed and compared. DA occurred in 3 males and 4 females. They occurred from 24 to 62 years of age, showing the mean age of 42.7 years. 5 of the 7 tumors occurred in the maxilla, and all of them in the anterior region, showing predilection for the maxillary anterior regions. There was no recurrence. Radiographically, they showed well demarcated unilocular or multilocular radiolucency. AF occurred in 5 males and 2 female. They occurred from 6 to 29 years of age, showing the mean age of 14 years. All tumors occurred in the mandibular molar area. Recurrence was recognized in 1 case. Although DA and AF showed similar histopathologic features, they showed different clinical behaviors. While DA showed predilection for the anterior maxilla, AF did for posterior mandible. While DA occurred mainly in adults, AF did in adolescents. Recurrence was recognized not in DA but in AF. Therefore, DA and AF should be differentiated from each other in spite of similar histopathologic findings

Glandular odontogenic cyst (GOC) is a rare odontogenic cyst, which shows cystic structures lined by stratified squamous epithelium with various thickness. Glandular duct-like spaces lined by eosinophilic cuboidal or columnar cells constitute the epithelial surface. The purpose of this study was to present 7 cases of GOC retrieved from the files of the Department of Oral Pathology, Seoul National University Dental Hospital and to investigate the immunohistochemical expression of cytokeratins (CKs) in the epithelial components. A total of 7 GOCs were reviewed clinically and radiographically and immunostainning for CK 5, 7, 14, 18 and CK-pan were performed. There were five males and two females aged from 36 to 53 years (mean 45 years). Maxilla was more affected than mandibles (6:1). Radiographically, all cases showed multilocular radiolucencies with well-defined borders. Histologically, lining epithelium of GOC was composed of nonkeratinized stratified epithelial cells with focal plaque-like or whirl pool-like thickenings. Surface epithelial layer contained eosinophilic cuboidal cells or mucous cells. Mucin pools of microcystic areas was also detected in the epithelium. Immunohistochemical study demonstrated that epithelium of GOCs was positively reactive for CK 5 7, 14 and CK-pan with a slight variation in their patterns and there was no reaction for CK 18.