Parotid gland ancient schwannoma is an extremely rare entity, with only 6 cases reported to date. Ancient schwannoma present degenerative alteration, including cystic changes, hyalinizing stroma, hemorrhages, infiltration of macrophages, and cellular atypia with hyperchromatic nuclei. These factors have the potential to mimic malignant tumors, resulting in an overestimation of diagnosis and subsequent inappropriate management. In the present case, we report a case of parotid gland ancient schwannoma, which developed relatively fast degenerative alteration without a large-sized mass. We reviewed all the cases of parotid ancient schwannoma, and suggest that the character of parotid gland tissue can deceive the change of tumor growth size. We also suspect that pre-surgical manipulation, such as FNAB or CNB, can cause degenerative changes in a relative short period. It is important to consider reactive degenerative alteration of schwannoma, and not to misinterpret as a malignant entities, notably when needle biopsy history is present.

Cemento-ossifying fibroma (COF) is classified as a fibro-osseous lesion and usually presents as a progressively growing lesion that can reach a large size if left untreated. Fibrous dysplasia (FD) is a non-neoplastic development that affects the craniofacial bones and is characterized by painless hypertrophy due to the replacement of bone by abnormal fibrous tissue. Herein, a case of concurrent occurrence of COF and FD involving the right mandible is described in a 14-year-old male patient. In this review, the current knowledge of FD and COF is summarized, emphasizing the importance of integrating the understanding of clinical, radiographic, and histopathological features. In addition, the relevant aspects associated with differential diagnosis and patient care are evaluated.

Langerhans cell histiocytosis (LCH) is a rare disease that arises from an abnormal increase in histiocytes. Due to its rare occurrence, the diagnosis of LCH is often delayed or missed. This report presents a case of LCH in a 16-month-old girl. After biopsy, the patient’s previous medical records were obtained. The records described the presence of a yellowish plaque on the forehead since birth, a characteristic feature of LCH. Earlier knowledge of this medical history would have helped facilitate the diagnosis of LCH. This report aims to inform clinicians of the clinical and histopathological features of LCH in order to aid in the early diagnosis of this disease, which can occur in infancy.

Mucoepidermoid carcinoma (MEC) is the most prevalent malignant tumor originating from the salivary gland. The gradation of MEC is determined histologically based on cellular composition, with high-grade MEC presenting with distinct characteristics and clinical implications. A 56-year-old male presented with a 3-month history of right facial swelling and a recent onset of pain. A subsequent biopsy confirmed a malignant epithelial tumor, with further imaging assisting in determining the surgical approach. Comprehensive surgery, involving the removal of the right submandibular gland and reconstructive procedures, was undertaken. Histopathological evaluation post-surgery confirmed a high-grade MEC. The differentiation between inflammatory conditions and neoplastic lesions in the orofacial region can be challenging. The gradation of MEC is important in guiding therapeutic decisions. Among various classification systems, the Brandwein system offers detailed histopathological criteria that correlate reliably with clinical features. High-grade MECs, although less frequent, are aggressive and have a lower 5-year survival rate. Accurate histopathological diagnosis is crucial in devising an effective treatment plan. The presented case underlines the importance of a meticulous yet periodic follow-up, considering the aggressive nature of high-grade MECs.

After the Fukushima nuclear power plant accident in 2011, interest in technology for evaluating residents’ exposure to effluents generated from nuclear power plants at the time of the accident has increased. KHNP has developed the S-REDAP program and is using it to evaluate radiation dose and recommend resident protection measures in the event of a nuclear power plant emergency. Its main functions are source term evaluation, atmospheric diffusion evaluation, radiation dose evaluation, etc. Based on these evaluations, resident protection measures are evaluated. In Japan, evaluation is conducted through a program called SPEEDI-MP (System for Prediction of Environmental Emergency Dose Information Multi-model Package) created by JAEA (Japan Atomic Energy Agency). Similar to S-REDAP, the program also evaluates effluents emitted from nuclear facilities through source term evaluation and atmospheric diffusion factor evaluation. In JAEA, through a program using SPEEDI-MP, the source term evaluation was performed in collaboration with NSC (Nuclear Safety Commission) in the event of the Fukushima nuclear plant accident, and dose evaluation in Japan was performed 2 months as an atmospheric diffusion factor using meteorological data for 2 days. Through comparative analysis of evaluation data from Japan, improvements to the current program be derived.

A variety of microorganisms are contained in the groundwater and surrounding environment at the depth of a deep geological repository, and could adversely affect the integrity and/or safety of the facility under certain thermal, hydraulic and chemical conditions. In particular, microbial activity (in the buffer and backfill) around the canister can cause corrosion of the canister through sulfide production by sulfate-reducing bacteria (SRB), and subsequently promote radionuclide release through the corroded part. Namely, this phenomenon is important in a perspective of performance assessment since it will have an impact on the post-closure exposure dose in the biosphere by accelerating radionuclide leakage into the near-field due to deterioration of the canister integrity In Finland, the performance assessment on microbial activity in buffer, backfill, and plug was performed for the licensing. However, in Korea, researches relevant to microbial activity are only in the early stage as of now. Accordingly, in this study, we draw initial considerations for the performance assessment on the phenomenon in the domestic facility based on review results for the methodology carried out as part of operating license application (i.e. SC-OLA). Studies on the performance assessment of microbial activity in Finland were mainly performed: (a) to investigate complex interactions among microorganisms in the repository by analyzing both indigenous and exogenous microorganisms through drilling, geological and geochemical analysis, (b) to identify microbial interactions at the buffer, backfill, and host rock interface for specific microorganisms that may affect activity of other microorganisms and integrity of the repository, (c) to analyze canister corrosion caused by microbial activity, particularly sulfide production by SRB, and (d) to characterize microbial illitization of montmorillonite that could affect permeability, hydraulic conductivity, and structural integrity of the repository. From reviewing studies above, it is judged that studies labelled as (b) through (d) are applicable to the performance assessment of microbial activity for the domestic facility regardless of specific conditions in Korea. However, for study labelled as (a), the following data on reflecting domestic conditions should be additionally obtained: (1) radionuclide inventory and temperature in spent nuclear fuel, (2) swelling pressure and organic carbon content of bentonite, and (3) size, shape, and gas composition of pores in bentonite. Results of this study could be directly applied to the design and performance assessment for buffer and backfill components, provided that input data specific to the domestic disposal facility is prepared for the assessment required.

췌석은 만성췌장염에서 흔히 동반되는 소견으로 반복되는 복통과 췌장염의 원인이 될 수 있다. 췌석은 췌관 협착과 자주 동반되고 췌관내 박혀 있는 경우가 많아 바스켓을 이용하여 제거하기 어렵다. 체외충격파쇄석술(ESWL)로 치료하기도 하나 반복 시술이 필요하고 성공률도 높지 않았다. 최근에 개발된 SpyGlass™ DS II (Boston Scientific, Marlborough, MA, USA)는 직경이 3.5 mm로 가늘어 췌관이 확장되어 있을 때 안으로 삽입이 가능하게 되었다. 그리고 직접 췌석을 보면서 전기수압쇄석술(EHL)이나 레이저 유도 쇄석술(laser lithotripsy)를 시행하며 췌석을 제거해 볼 수 있게 되었다. 본고에서는 SpyGlass™ DS II와 EHL을 이용하여 10 mm 이상의 다발성 췌석을 제거하는 방법을 소개하고자 한다.

EBV-positive mucocutaneous ulcer (EBVMCU) is an indolent, superficial lymphoproliferative disorder that occurs in either iatrogenic or age-associated immunocompromised patients with latent Epstein-Barr virus (EBV) infection. Although EBVMCU is histologically similar with other lymphoproliferative disorders, such as EBV-positive diffuse large B cell lymphoma, the diseases are classified as distinct entities by the World Health Organization with different clinical manifestations, prognosis, and genetic profiles. EBVMCU commonly shows spontaneous regression by conservative management, reduction or cessation of immunosuppressive treatment, but local progression is possible. Complete remission of disease can be achieved with combination of surgical resection, chemotherapy and local radiation therapy. Herein, we report 2 cases of oral superficial lymphoproliferative disorders arising adjacent to the gnathic bone with striking differences in prognosis and bone involvement. One of the cases induced extensive osteomyelitis in the underlying bone. Furthermore, we discussed the differential diagnosis of EBVMCU and reviewed the former literature.

Malignant melanoma is a highly malignant tumor derived from melanocyte. Malignant melanoma of the oral cavity occurs mainly in the palatine mucosa and the maxillary gingiva in men in their 50s. Malignant melanoma can be divided into pigmented and non-pigmented(amelanotic). Among them, non-pigmented malignant melanoma accounts for 2-8% of all malignant melanomas. Pigmented malignant melanoma is detected through changes in pigmentation, whereas non-pigmented malignant melanoma is characterized by no pattern of color change. In this study, at the initial visit, a malignant lesion was suspected and a biopsy was performed. According to the biopsy results, it was diagnosed as polymorphic sarcoma, but the histological examination performed during the operation revealed that it was amelanotic melanoma. As such, the differential diagnosis is important because there is no clinical change in non-pigmented malignant melanoma. Diseases to be differentially diagnosed when non-pigmented malignant melanoma occurs in the oral cavity include squamous cell carcinoma, lymphoma, sarcoma, inflammation, and osteomyelitis. In this study, we report a case that showed the histopathological characteristics of malignant melanoma without superficial pigmentation.

Plunging ranula is a mucous retention cyst with extension below to the mylohyoid muscle. It can occur by an extravasation of saliva from the salivary gland due to trauma or obstruction of the duct. Fluid from the obstructed gland penetrate through the defect of mylohyoid muscle or through the posterior edge of mylohyoid muscle, and spreading to the cervical area. The “tail sign” has been widely reported as pathognomonic for their diagnosis. It indicates the communication between the collapsed sublingual and submandibular space over the posterior edge of the mylohyoid muscle. In this case, in addition to simple ranula in the right floor of mouth, MRI findings showed homogeneous contrast enhancement in front of the right cervical carotid artery and in the deep part of sternocleidomastoid muscle, but tail sign was not observed. Therefore it was clinically diagnosed as a branchial cleft cyst and was removed through surgical procedure. As a result of the final pathologic biopsy, the lesion, which has been suggested to be simple ranula in the floor of mouth, was diagnosed as reactive pyogenic granuloma, and the cervical lesion was diagnosed as a plunging ranula. This is a case report in which these two lesions are decided to have been separated from one before surgery. This report indicate that plunging ranula can be observed without tail sign and how to make an accurate diagnosis of plunging ranula by reporting misdiagnosis case.

Telangiectatic osteosarcoma(TAEOS) is a rare subtype of osteosarcoma(OS) composed of blood-filled or empty cystic architecture simulating aneurysmal bone cyst. TAEOSs account for 2-12% of all OSs. TAEOSs mostly develop around knee and proximal humerus, but TAEOSs of the jaws are rare. To the best of my knowledge, this is the fourth case of primary TAEOS affecting the jaws. A 36-year-old female who had been previously diagnosed osteosarcoma by biopsy reported with a chief complaint of throbbing and swelling of the right mandible. The patient received neoadjuvant chemotherapy followed by hemi-mandibulectomy. After surgery, patient received adjuvant chemotherapy. The patient is free of disease for 6 months after surgery. TAEOSs are mimicking other benign entities, such as aneurysmal bone cyst and central giant cell granuloma. Thus, careful diagnosis through thorough radiographic and histopathologic evaluation is important to establish a treatment plan, prognosis, prediction and management strategy.

Mucosal malignant melanoma is an uncommon tumor of the head and neck, and patient cannot easily recognize the lesion. Most patients are diagnosed with advanced lesions, and the 5-year survival rate is very low. Therefore, intraoral pigmented lesions require an incisional biopsy for differential diagnosis from malignant melanoma. As the size of the tumor increases, lesion showing vertical growth and lymph node metastasis increases, and the prognosis becomes poor. In this study, we report a case of mucosal malignant melanoma in the oral cavity that shows radial growth and no lymph node metastasis despite its relatively large size.

Many countries plan to dispose of spent nuclear fuel through deep geological disposal system. In Korea, a plan is being established for the construction of a deep disposal facility to dispose of highlevel radioactive waste (or spent nuclear fuel). For construction of a deep geological repository, the NSSC (Nuclear Safety and Security Commission) stipulate that detailed technical standards for location, structure, and disposal system of deep geological repository are determined and announced by the Nuclear Safety and Security Commission Notification. Therefore, the regulatory body should carry out the process of regulatory review whether the technical standards developed by the implementer are suitable for the IAEA’s recommendations and guidelines and domestic conditions. In this process, there are many difficulties and uncertainties in terms of time and cost to independently develop safety factors in Korea by referring to the IAEA reports. So, this study intends to investigate and analyze regulatory cases for important safety factors through cases of overseas leading countries in deep geological disposal project. There are two regulatory cases intensively investigated in this study. The first is a regulatory case of regulatory bodies and external experts on the safety case, and the second is a regulatory review case in the process of site selection factor selection. In case of regulatory review of safety case, Sweden and France were selected as the representative target countries. In Sweden, safety cases such as SR-97, SR-Can, and SR-Site have been developed and there are cases of active regulatory review by regulatory agencies in the RD&D process. In France, several safety cases based on sedimentary rocks were developed and the OECD/NEA IRT (International Review Team) was inquired for review for each safety case. The site selection process is divided into a preliminary site selection stage, a site investigation stage, and a site selection and application stage. In each stage, evaluation to select a safe site is carried out using allocated siting factors of that stage. The IAEA SSG-14 report describes aspects that implementers consider in the site selection process and, with this reference, many countries are developing various siting factors and assessment methodologies in consideration of their domestic bedrock condition and geological positions. As a representative example, in Japan which is highly affected by earthquakes and igneous activities, the siting factor is classified into EF (Evaluation Factors) and FF (Favoulable Factors). So, site assessment is conducted preferentially using EF related to earthquakes and igneous activity.

동물은 그들의 필요와 외부 자극, 그리고 주변 환경에 반응하면서 특정한 행동과 이동 패턴을 보이며, 생활하면서 대부분의 시간을 보내는 일정한 영역인 행동권(home range)을 가진다. 행동권은 종의 존속과 보전에 매우 중요한 영역이라는 점에 기반하여 해외에서는 행동권 추정 방법론 개발 및 정책 반영이 활발하게 이루어지고 있다. 원격 추적 기술의 발전으로 인해 좌표간 시간 간격이 줄어들며 정밀해진 동물 추적 데이터는 기존 행동권 방법론에 한계점을 드러냈으며, 이를 보완하기 위하여 다양한 새로운 방법론이 개발되었다. 하지만, 국내 행동권 연구는 아직 더딘 편이며 새로이 개발된 방법론 도입도 전혀 이루어지지 않고 있는 상태이다. 본 연구는 동물 행동권의 더욱 정확한 추정을 목적으로 꾸준하게 개발되어 온 해외의 방법론들을 정리 및 소개하여 국내 도입을 촉진하는 것을 목적으로 한다. 먼저 크게 기하학적 그리고 통계적 추정 방법론으로 나눈 후 좌표들이 독립일 때와 자기상관성이 존재할 때의 경우로 나누어 총 7가지의 행동권 추정 방법론을 비교 및 고찰하였다. 실제 전남 신안군 불무기도에 번식하는 괭이갈매기(Larus Crassirostris)의 6월 한 달간 GPS 위치 추적 정보를 사용해 본 연구에서 소개한 방법론을 적용하여 행동권을 도출하였 다. 행동권 결과를 비교분석 함으로써 각 방법론의 특징 및 한계점을 논의하였으며, 향후 동물 행동권을 분석하고자 하는 연구자가 본인이 가지고 있는 데이터 특성과 분석 목적에 알맞는 방법론을 선택할 수 있도록 행동권 분석 방법론 선택 의사결정 가이드라인을 제시하였다.

Pancreatic acinar cell carcinoma (ACC) is a rare neoplasm accounting less than 1% of malignant pancreatic tumors. A 47-year-old male patient visited the emergency room with epigastric pain. Computed tomography or magnetic resonance imaging revealed a 4.7-cm heterogeneously enhanced solid and cystic mass with internal necrosis located in the head of the pancreas. Radiological diagnosis was borderline malignancy such as neuroendocrine tumor or solid pseudopapillary neoplasm. Two months later, the necrotic mass in the pancreas head had grown up to 11 cm, compressing the duodenum, superior mesenteric vein, and proximal transverse colon. Pylorus preserving pancreatoduodenectomy with segmental resection of transverse colon was performed. Histopathological examination revealed that the tumor was pancreatic ACC. The patient recovered without any complication and was doing well without recurrence for 12 months after surgery.

Sarcomatous transformation of fibrous dysplasia (FD) is rare and can occur in patients with McCune-Albright syndrome (MAS). To date, there have been several cases of malignant transformation of FD in the craniofacial area of patients with MAS. Here, we report an additional case of secondary osteosarcoma arising from FD in the mandible of a 41-year-old woman with MAS. The patient complained of rapid swelling in the right facial area, which was initially misdiagnosed as soft tissue sarcoma at another hospital. After neoadjuvant concurrent chemoradiotherapy resulting in poor response, the lesion was surgically resected in our hospital, and the final diagnosis of secondary osteosarcoma was rendered. Currently, post-operative adjuvant chemotherapy is in progress. As a result of our review of 17 reported cases showing malignant transformation in FD/MAS, the M/F ratio was 1:1.1, and the median age at onset of malignancy was 28.6 years. The most commonly affected site was the craniofacial bones (n=13; 76%), and the most common histopathologic type of malignancy was osteosarcoma (n=14; 82%). More than half of the patients (8/15; 53.3%) died within 1 year, mainly due to lung metastasis (6/8; 75%). Taken together, since MAS patients with malignant transformation of FD have a relatively poor prognosis, accurate diagnosis based on histopathologic findings as well as clinical and radiographic information is important to select optimal treatment.

Salivary duct carcinoma is a highly malignant tumor that arises from salivary gland. Pathologically, Salivary duct carcinoma is similar to high-grade breast ductal carcinoma. The tumor is commonly associated with pain and facial paralysis and is known to have high rates of recurrence and metastasis. Surgical resection and postoperative radiation is mainstream of the treatment. In this study, we report a case of this tumor which was seen predominantly benign-looking in fine needle aspiration biopsy. The features of this tumor are presented with a review of literature.

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.

Adenoid cystic carcinoma(ACC) is an uncommon tumor of the head and neck. It is one of the most common malignant tumor of the salivary glands. Although ACC has clear pathologic features, it can be diagnosed as a benign lesion in terms of cytological and radiologic aspects. In this paper, we report a rare case of ACCACC on tongue that is diagnosed as ACC but appears as a benign lesion in cytological and radiologic views.