A novel cell line that retains the morphological characteristics of the cells and matrix of odontogenic myxoma

Little is known about the histogenesis of the human odontogenic myxoma or the relation between tumour cells and the matrix. In order to attempt to remedy this situation, we established and investigated a cell line derived from a human odontogenic myxoma. To our knowledge this is the first cell line derived from this tumour. The cell line, named Mix 1, preserved features of the tumour cells. Mix 1 cells expressed vimentin, type I collagen, fibronectin, tenascin and hyaluronic acid. Ultrastructural analysis of cells of the tumour and cell line demonstrated similarities, both containing Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells. Ultrastructural analysis showed the matrix to be represented by bundles of collagen fibrils in the tumour, and by irregular filaments in cultures more than 60 days old. The Mix 1 cell line promises to be an excellent model for investigating the biology of the odontogenic myxoma.     

Comparison of radiographic and MRI features of a root-diverging odontogenic myxoma,with discussion of the differential diagnosis of lesions likely to move roots

Lesions that can produce divergence of the roots of teeth in the mandible include odontogenic cysts (odontogenic keratocysts, lateral periodontal cysts and radicular cysts), ameloblastomas, odontogenic myxomas, central giant cell granulomas, adenomatoid odontogenic tumors and aneurismal bone cysts, and other tumors. Moreover most benign jaw lesions can do this occasionally. However, when lesions--which show interradicular tear-shaped radiolucencies--are small it is often difficult to interpret them radiographically, because they do not show characteristic radiographic features. We describe a comparison of radiographic and magnetic resonance (MR) features of a root-diverging odontogenic myxoma, with discussion of the differential diagnosis of lesions likely to move roots. In addition, we discuss radiographic and MR features of possible lesions, which show similar radiographic findings to odontogenic myxoma.     

Mandibular reconstruction using fresh frozen bone allograft after conservative enucleation of a mandibular odontogenic myxoma

The purpose of this article was to report the clinical, radiographic, and histological findings about a case of a young woman affected by a mandibular odontogenic myxoma. Conservative tumor resection was followed by immediate reconstructive treatment using fresh-frozen human bone graft, instead of autologous bone graft, as material for bone regeneration. Odontogenic myxoma, according to the World Health Organization, is classified as a benign tumor of mesenchymal origin whether or not containing odontogenic epithelium. Radiological and histological examination of the lesion confirmed the presence of an odontogenic myxoma, which was 21.2 mm high and 47.6 mm long; the lesion underwent biopsy evaluation before enucleation. According to literature and with the aim of a patient free of disease, conservative enucleation of the lesion was performed. The residual bone defect was filled with fresh-frozen bone allograft. At 6 months after surgery, no evidence of major complications was observed; the computed tomography scan revealed effective bone regeneration through the grafted area. The use of fresh-frozen bone allograft, thanks to its osteoinductive and osteoconductive properties, may represent an optional choice for reconstruction of bone defects after jaw tumor removal.     

44例牙源性纤维瘤临床病理分析

目的 研究牙源性纤维瘤的临床病理特点。方法 按世界卫生组织（WHO）1992年牙源性肿瘤分类标准对44例牙源性纤维瘤的临床病理特点及生物学行为进行回顾性研究。结果 本组44例中，女31例，男13例。发病年龄2－70岁，平均29岁。中心型5例，周边型39例。上颌19例，下颌25例。X线及手术中见4例牙槽骨明显破坏。术后有4例复发。组织学上表现为WHO型39例、单纯型4例和牙源性颗粒细胞瘤1例。肿瘤无明显包膜，边界尚清。结论 牙源性纤维瘤不是单一性肿瘤，组织学上表现为WHO型、单纯型和牙源性颗粒细胞瘤。诊断时应与增殖性牙滤泡、粘液瘤等相鉴别。     

Odontogenic squamous cell carcinoma with osseous metaplasia

Intra-osseous carcinomas of the jaw are rare tumours, thought to arise from residual elements of the odontogenic epithelium. We report an additional case which, unusually, was characterised by marked osseous metaplasia. We propose that the new bone formed around the tumour is the result of an epithelial-mesenchymal interaction between malignant odontogenic epithelium and osteogenic precursor cells in the surrounding stroma.     

Peripheral Odontogenic Myxoma: A Review of the Literature and Report of Two Cases

Two cases of peripheral odontogenic myxoma with a verifiable location in gingival soft tissue and without bone involvement were compared with those reported in the literature. This study showed that they form a distinct albeit rare clinical entity with a potential to grow into large disfiguring lesions. The probability that small peripheral odontogenic myxomas are interpreted as edematous irritation fibromas may contribute to the small number of peripheral odontogenic myxomas recorded in the literature. The differential diagnosis of soft tissue myxoid proliferations is discussed.     

Soft tissue myxoma of the gingiva: report of a case and review of the literature of soft tissue myxoma in the oral region

Soft tissue myxoma of the oral cavity is extremely rare. We present a case of soft tissue myxoma arising from a mandibular anterior gingiva in a 51-year-old male patient. Histological examination showed islands of odontogenic epithelium scattered in the mucinous stroma. This lesion was supposed to have a odontogenic origin. The clinical differences between soft tissue myxoma with bone destruction and those without bone destruction are also discussed by a review of the literature.     

The Management of Aggressive Cysts of the Jaws

There are essentially six types of aggressive cysts of the jaws that require special attention, so as to avoid recurrence, or even worse, widespread disease. They include, botryoid cysts, cysts in which carcinoma’s arise, glandular odontogenic cysts, calcifying cystic odontogenic tumour, previously called calcifying odontogenic cyst and unicystic ameloblastoma and keratocystic odontogenic tumor, previously called odontogenic keratocysts. The estimated incidence of these cysts, based on some review studies has been discussed. The main issue, however, when treating a cyst of the jaws is; how sure can one be that the lesion is benign or potentially aggressive? In order to answer this question it is important to know how these cysts commonly present. The clinical presentation, frequency of occurrence and suggested modes of treatment has been addressed.     

Odontogenic myxoma: histochemical and ultrastructural study

Three cases of odontogenic myxoma are presented, two of which were located in the mandible and one in the maxilla. All cases demonstrated similar morphology by light microscopy. Immunohistochemical studies demonstrated positive reaction with antibodies to vimentin and actin, and negative reaction to antibody to S-100 protein. A 127-day-old human tooth bud was used as a control. The ultrastructural features performed on Case 3, when combined with the immunohistochemical findings suggest that the cells comprising odontogenic myxoma are of myofibroblastic origin.     

牙源性角化囊肿的手术治疗：保守性或根治性方法

牙源性角化囊肿（odontogenic keratocyst，OKC）因其侵袭性行为、组织学和遗传学方面的新发现，在WHO的分类中已命名为牙源性角化囊性瘤（keratocystic odontogenic tumour，KCOT）。本文复习了这种病变的生物学特点，并结合笔者的研究经验和相关文献资料分别介绍保守性和根治性治疗策略。     

So-called calcifying odontogenic cyst: review and discussion on the terminology and classification

Toida M: So-called calcifying odontogenic cyst: review and discussion on the terminology and classification. J Oral Pathol Med 1998; 27: 49–52. © Munks-gaard, 1998.
The so-called calcifying odontogenic cyst (COC) shows extensive diversity in its clinico-histopathological appearances and biological behaviour. Because of this diversity, there has been confusion and disagreement on the terminology and classification of this lesion. The attempts at classification of COC may be divided into two concepts. The first concept is the "monistic" one that all COCs are neoplastic in nature, even though the majority are cystic in architecture and appear to be non-neoplastic. The second is the "dualistic" concept that COC contains two entities: a cyst and a neoplasm. Although the World Health Organization (WHO) classified COC as an odontogenic tumour in 1992 based on the former concept, current thinking favors strongly the latter one. In this article, several previous classifications of COC in the literature are discussed and a new simple classification scheme based on the "dualistic" concept is proposed.     

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提要：外周性牙源性肿瘤又称骨外型牙源性肿瘤或软组织牙源性肿瘤,主要发生在牙龈,包括牙源性真性肿瘤及错构瘤。外周性牙源性肿瘤约占所有牙源性肿瘤的4%左右,英文文献表明其中外周性牙源性纤维瘤最多见,其次是外周性成釉细胞瘤及外周性牙源性钙化囊性瘤。外周性牙源性肿瘤临床上容易与牙龈发生的炎症性或反应性病变相混淆,明确诊断依赖组织病理学检查。外周性牙源性肿瘤不包括骨内型牙源性肿瘤穿破骨皮质侵犯牙龈。外周性牙源性肿瘤预后普遍好于相应的骨内型肿瘤,但切除不彻底仍可复发,建议长期随访。     

Adenomatoid odontogenic tumour: A case report

Adenomatoid odontogenic tumour (AOT) is a rare benign odontogenic tumour characterized by a progressively slow growing pattern and symptomless behavior. The differential diagnosis between AOT and other odontogenic tumours, such as ameloblastoma, should be well conducted in order to avoid extensive ablative surgery. This report presents an unusual case of an 11-year-old male patient who referred to the oral surgeon due to a significant painless gingival swelling in the anterior mandible. A panoramic X-ray revealed a round radiolucid image of an intraosseous lesion with well defined boards and related to the left lateral incisor and left canine. The Computerized Tomography was performed and the sagittal sections revealed a tooth image in contact with the inferior board of the tumour. Additionally, the coronal sections showed the presence of a tooth inside the lesion. Several calcifying nodules could be distinguished within the cystic area. The clinical diagnostic hypothesis was of calcifying epithelium odontogenic tumour but the histological sections were consistent with AOT. The tumour was enucleated under local anesthesia. After one year follow-up there were no signs of reoccurrence. With respect to the distinguishing tumour enlargement and localization in the lower jaw, the reported case is an uncommon example of AOT.     

External tooth resorption associated with a peripheral odontogenic fibroma: review and case report

The purpose of the study is to document a rare case of a peripheral odontogenic fibroma with associated cervical and coronal tooth resorption in a 38 year old woman. Histopathological features are described, the clinical management outlined and follow‐up observations over 27 years detailed. The exophytic firm lesion, coral pink in appearance, located on the labial aspect of a maxillary right lateral incisor was excised, fixed in formalin and prepared for histological evaluation. The resorption cavity and adjacent soft tissue were treated by the topical application of trichloroacetic acid prior to restoration with a glass‐ionomer cement and subsequent root canal treatment. Histologically, the body of the lesion was characterized by the presence of odontogenic epithelium embedded in a mature fibrous stroma. Areas of dystrophic calcification could also be identified. The features were consistent with a diagnosis of a peripheral odontogenic fibroma. The clinical result of treatment assessed 27 years postoperatively showed no evidence of recurrence of the peripheral odontogenic fibroma. External cervical and coronal tooth resorption can, on rare occasions, prove to be a clinical feature associated with peripheral odontogenic fibroma. Treatment of the tumour mass and the resorptive lesion can provide a successful outcome.     

Central odontogenic fibroma current concepts

The author reviews current knowledge concerning the central odontogenic fibroma, which at present is incompletely understood, and reaches the following conclusions. 1) The separation of this lesion into simple and WHO types remains valid because they exhibit different histologic features. However, more care should be taken in rendering the diagnosis of the WHO type than in the past; unlike the simple type, it is a fibroblastic lesion. 2) Complex central odontogenic fibroma is a more appropriate term than the WHO type because the WHO does not use the latter term in its 1992 manual. 3) The microscopic distinction of simple odontogenic fibroma from desmoplastic fibroma remains difficult in some cases. 4) The granular cell odontogenic tumor, which has sometimes been referred to as a type of odontogenic fibroma, is a separate entity, although some simple odontogenic fibromas exhibit scattered granular cells. 5) The separation of lesions that have been reported recently as odontogenic fibromas with giant cell reactions from central giant cell granulomas that exhibit foci of odontogenic epithelium requires further study.     

A case of malignant myxoma (myxosarcoma) of the maxilla

Abstract – A centrally located maxillary myxoma with malignant histologic appearance and aggressive clinical course is reported in a 40-yr-old man. The gelatinous polypoid tumor mass was diagnosed as a myxoma in the first biopsy. The tumor recurred rapidly (within 3 wk) eroding the bony structures of the maxillary sinus and the hard palate and infiltrating the adjacent soft tissues. In repeated biopsy (as well as reassessment of the first biopsy) the tumor was found to be composed of plump stellate cells, some of which were pleomorphic with atypical and bizarre mitotic figures. The amorphic myxoid matrix contained acid mucopolysaccharides and was completely devoid of lipids. Electron microscopy demonstrated that the tumor cells were identical to fibroblasts, which is consistent with the appearance of myxoma cells. When radiotherapy was unsuccessful, we removed the left maxilla with orbital excenteration and reconstructed the jaw. Three years later the patient died accidentally. At autopsy, no recurrence of myxoma or distant metastases were found. Due to the malignant histologic appearance and the aggressive clinical course, this tumor can be called an odontogenic myxosarcoma and should be added to the WHO classification as a malignant variant of odontogenic myxoma.     

Variants of the adenomatoid odontogenic tumor with a note on tumor origin

Three rare variants of the adenomatoid odontogenic tumor (AOT) are described. A follicular AOT associated with an impacted and displaced 28, an extra-follicular variant mimicking a radicular cyst around the apex of 23 and a peripheral (epulis-like) variant exhibiting a periodontal bone defect palatal to 21. On reappraisal of the origin and pathogenesis of the AOT, it would seem that this tumor or hamartomatous lesion is derived from odontogenic epithelium of the dental lamina complex or its remnants.     

周边型牙源性纤维瘤35例临床病理研究

目的 :总结周边型牙源性纤维瘤的临床病理特点。方法 :按WHO(1992 )牙源性肿瘤分类标准对 35例周边型牙源性纤维瘤的临床病理资料进行回顾性分析。结果 :35例中 ,男性 14例 ,女性 2 1例 ;平均年龄 31岁 ;上颌牙龈 14例 ,下颌牙龈 2 0例。肿块为局部软组织突出表现。X线片和手术中见五例牙槽骨有吸收改变。三例术后复发。组织学上 ,肿瘤由致密结缔组织组成 ,含数量不等的成纤维细胞 ,一例伴有颗粒细胞。肿瘤边界尚清 ,缺少明显包膜。结论 :周边型牙源性纤维瘤临床表现与龈瘤不能区分 ,组织学主要为WHO型牙源性纤维瘤 ,手术切除不彻底易复发。     

The central odontogenic fibroma. Clinical and morphologic studies.

The clinical, pathologic, and ultrastructural features and pertinent case history of an 11-year-old boy with a rare benign odontogenic neoplasm, the central odontogenic fibroma, are presented. A review of the literature reveals seven other lesions with clinical and pathologic findings similar to those of this case. This study supports the concept that the central odontogenic fibroma is a distinct odontogenic neoplasm of bone which occurs most commonly in the mandible as a multilocular, radiolucent, and slowly growing expansile lesion with no tendency to recur after surgical enucleation. The ultrastructural findings indicate that the central odontogenic fibroma and the odontogenic myxoma share many common morphologic features and have an apparently similar histogenesis.     

Immunohistochemical demonstration of enamel proteins in odontogenic tumors

Immunohistochemical localization of two enamel proteins, amelogenin and enamelin, in comparison with that of keratin, was determined in odontogenic tumors and the allied lesions in order to verify functional differentiation of the tumor cells as ameloblasts. Amelogenin and enamelin were demonstrated in small mineralized foci and in the tumor cells surrounding them in adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), and calcifying odontogenic cyst (COC). Hyaline droplets in AOT showed positive staining for both enamel proteins. These mineralized and hyaline materials were not positive for keratin, although tumor cells were positive. On the other hand, no immunoreaction for enamel proteins was obtained in ameloblastoima and odontogenic epithelial cell nests within myxoma and epulis. The results suggest that tumor cells of AOT and CEOT and lining epithelial cells of COC show ameloblastic differentiation in part, but that ameloblastoma cells do not attain functional matauration as secretory phase ameloblasts.