Langerhans cell histiocytosis (LCH) is a rare clinicopathologic disorder characterized by proliferation of histiocyte- like cells (langerhans cell histiocytes) accompanied by varying other inflammatory cells. LCH commonly involves the oral and maxillofacial region, but is very rarely seen. Then LCH has made it difficult to investigate the clinical and histological aspects. We investigated LCH of oral and maxillofacial region and analyzed clinical and histological characteristics. We reviewed the records of all patients who were diagnosed as LCH, retrospectively. Data included patient’s age, sex, chief complaint, clinical diagnoses, radiologic and histologic reports, and clinical course. We analyzed clinical and histological characteristics. From 2000 to 2007, 8 patients were diagnosed as LCH. 7 were children and 1 was adult. All cases involved mandible. Clinical type of all cases were“eosinophilic granuloma”. 6 cases were classified as“unifocal disease”and 2 cases were“multifocal single system diseases”. Microscopic findings commonly showed numerous histiocytes with eosinophilic cytoplasm (langerhans histiocytes). In 6 cases, immunohistochemical study was accomplished and confirmed the diagnosis of LCH. 6 cases were cured and not recurred, and 2 cases had loss of follow- up. Unifocal disease type of LCH may arise in Korean people more frequently than in western people (75% Vs 49%). Therefore, the higher frequency of unifocal disease of LCH is expected to raise the cure rate and to improve patient prognosis in Korean patients with LCH.

Numerous bone cell culture models have been presented by the development of isolation and culturing techniques of cells. The culture of osteoblast-like cells of human origin with a specific osteoblastic phenotype has become an important experimental model in bone biology. Recently, it has become increasingly popular to utilize bone marrow cultures because these cultures are therefore thought to represent earlier stages of the osteoblast differentiation pathway. There is no report about culturing normal human osteoblast from oral and maxillofacial area. Primary cultured cells from oral and maxillofacial cancellous bone were analyzed by morphologic features, total DNA contents, ALP, osteocalcin and von Kossa staining positivity. The purpose of this study were to culture the cell population from oral and maxillofacial cancellous bone and to analyze the phenotypic expression of cultured normal human osteoblast by the bone marrow isolation technique. Growth curve of NHost showed about 45hrs of doubling time and about 70μ g/well of total DNA content. NHost showed spindle shaped cytoplasm with ovoid nucleus under preconfluency and after cellular differentiation, they formed irregular numerous nodules from stratified cellular layers under D medium. ALP activity was about 2 folds higher under control medium with 10nM 1,25(OH)2D3 than that under control medium. Osteocalcin expression was about seven folds higher under control medium with 100nM 1,25(OH)2D3 than that under control medium. Scattered mineralized nodules stained by von Kossa method were seen on the cellular layer under D medium. It suggested that NHost might be established from oral and maxillofacial area by characteristic cellular shape, ALP activity, osteocalcin expression and numerous mineralized nodules.