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%. 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. 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.

Mucoepidermoid carcinoma (MEC) is the most common malignant epithelial tumor of the salivary gland in the oral cavity. In South Korea, it occurs most frequently in the palate, retromolar area, floor of the mouth, buccal mucosa, and other areas of the oral cavity. MEC is rare in children and adolescents under 20 years of age, but it is the most common malignant salivary gland tumor in this group. Reconstructive surgery is often required due to cystic lesions or resection of malignancy in the oral cavity. Buccal fat pad (BFP) is a flap that is reliable and suitable for reconstructing oral defects because it has a low complication rate and small volume change over time. Case Presentation: We report the case of a 12-year-old female patient with low-grade MEC on light soft palate with no neck metastasis. After tumor resection the palatal mucosal defect was reconstructed with a BFP flap. Conclusion: The purpose of this article is to discuss the features and treatment methods of MEC that is rarely occurring in children, and the usefulness of BFP for reconstruction. Therefore, we will make a precise diagnosis and treatment as we examine the clinical feature and review the literature.

Pseudosarcomatous fibromatosis (PSF), also known as nodular fasciitis and pseudosarcomatous fasciitis, is a rare, benign proliferation of fibroblasts and myofibroblasts. It is often misdiagnosed as sarcoma because of its characteristic rapid progression, leading to unnecessary and aggressive surgery. Here we report a case of PSF found in the masseter muscle in a 26-year-old female. The mass that could be misdiagnosed because of its rapid growth characteristics was surgically excised by an intraoral approach and diagnosed as PSF by histopathologic examinations.

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.