Odontogenic Myxofibroma Research Articles

Odontogenic myxofibroma with HMGA2 overexpression and HMGA2 rearrangement

Odontogenic myxofibromas are variants of odontogenic myxomas that contain considerable amounts of collagen fibers in the myxoid stroma. Cytogenetic studies of odontogenic myxomas/myxofibromas have rarely been reported. This report describes the first case of an odontogenic myxofibroma presenting with HMGA2 protein overexpression and HMGA2 rearrangement in a 40-year-old woman. A 2.7-cm tumor in the premolar region of the right mandible was curettaged. There was no evidence of recurrence or metastasis at 12 months after the surgery. Histological examination revealed that the tumor comprised spindle or stellate cells with mild nuclear pleomorphism, abundant myxoid matrix and partly dense collagen fibers. Mitotic figures were rarely observed. Immunohistochemically, the tumor cells were diffusely positive for vimentin and HMGA2. Less than 1% of the tumor cells were positive for Ki-67. We detected split signals by interphase fluorescence in situ hybridization (FISH) in paraffin sections using HMGA2 break-apart probes. The breaks were certainly located within or near the HMGA2 gene. No rearrangement of the FUS gene was detected by FISH, implying discrimination from low-grade fibromyxoid sarcoma. It is suggested that HMGA2 rearrangement and HMGA2 protein overexpression may be associated with the tumorigenesis of odontogenic myxomas/myxofibromas, similar to the case for many other benign mesenchymal tumors.

Odontogenic myxofibroma synchronous with primary angiosarcoma of the spleen

Odontogenic myxofibroma of the temporomandibular joint (TMJ) is a rare tumour; moreover, primary splenic angiosarcoma (PAS) in paediatric patients is extremely rare. We report on a 15-year-old boy who presented with right TMJ swelling and subsequently developed epigastric and right upper quadrant pain. The TMJ swelling proved to be odontogenic myxofibroma and the abdominal pain was a result of primary splenic angiosarcoma with hepatic metastasis. We report for the first time the synchronous presentation of PAS and odontogenic myxofibroma in a paediatric patient, and we describe the radiological features along with the histological diagnosis and clinical outcome. Uptake in (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography is also described for the first time for both these tumours.

Clinicopathologic spectrum of the so-called calcifying odontogenic cysts: a study of 21 intraosseous cases with reconsideration of the terminology and classification.

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinicopathologic and behavioral features. Because of this diversity, there has been confusion and disagreement on the terminology and classification of these lesions. We reviewed the clinicopathologic features of 21 intraosseous cases that were previously diagnosed as COC or under related diagnostic terms. Based on the biologic behavior, the lesions of the present series were divided into three subgroups: cyst, benign tumor, and malignant tumor. Sixteen cases (nine men and seven women) proved to be unicystic lesions with (five cases) or without associated odontoma. The lining epithelium of the cystic lesions fulfilled the histologic criteria for COC proposed by the World Health Organization, and their overall clinicopathologic features were consistent with that of developmental odontogenic cysts. The age of patients from the cyst group peaked at the second decade. The maxilla was affected more often (69%) than the mandible, with a predilection for the canine-premolar region (62.5%). Thirteen patients with follow-up information revealed no recurrence following enucleation. The four cases in the benign tumor group had variable clinicopathologic features. Two cases were solid tumors consisting of ameloblastoma-like sheets of odontogenic epithelium that contained ghost cells/calcification foci and juxtaepithelial dentinoid. Both patients experienced multiple recurrences following conservative surgeries. The other two lesions contained typical areas of COC and other types of odontogenic tumors (one ameloblastoma and one odontogenic myxofibroma). All four lesions occurred in the mandible and were relatively large. In the present series one case identified as malignant tumor arose from a previously benign COC. The tumor shared some features of COC (ghost cell foci and dystrophic calcification) but also had prominent mitotic activity, nuclear and cytoplasmic pleomorphism, areas of tumor necrosis, and infiltrative/destructive growth. Recognizing the extreme diversity in clinicopathologic features and biologic behavior among the so-called COCs, we suggest that the term COC should be used to specifically designate the unicystic lesions with or without an associated odontoma, i.e., lesions of the cyst group, and other related lesions identified as benign tumor and malignant tumor should be termed and classified separately. A tentative scheme with respect to the terminology and classification for this group of disparately behaving lesions was herein proposed to reflect the likely difference of their nature.

A Case of Odontogenic Myxofibroma Occuring from Anterior Teeth to Premolar Area of Mandible

A Case of Odontogenic Myxofibroma Occuring from Anterior Teeth to Premolar Area of Mandible

Odontogenic Myxofibroma Arising From the Periodontal Ligament in the Maxillary Molar Region

A rare case of odontogenic myxofibroma, which arose from the periodontal ligament and expanded into the oral cavity resulting in an epulis-like lesion in a 52-year-old man, is reported including details of studies using lectin histochemistry, transmission electron microscopy (TEM), and immunohistochemistry. Most of the tumor cells, which appeared spindle-like with abundant rough endoplasmic reticulum and some microfilaments by TEM, showed immunoreactivity for mesenchymal markers. Some tumor cells, which were polygonal and contained many microfilaments and some filament bundles, were immunoreactive for muscle markers. The present case was considered to consist of many fibroblasts and some myofibroblasts.

下顎歯原性粘液線維腫の１例

A case report on a 26-year-old male with odontogenic myxofibroma of the left side mandible was presented.The patient was referred to our department with chief complaints of slight pain and swelling of the left side mandible.Radiographs revealed a large unilocular and radiolucent lesion in the left side mandible.An incisional biopsy examination was performed and a diagnosis of myxofibroma was then made.The tumor was well circumscribed showing apparent encapsulation.Microscopic sections disclosed an odontogenic epithelium composed mainly of large myxomatous tissue.The final diagnosis was myxofibroma of the odontogenic tissue in origin.

特異な石灰化物を伴った歯原性粘液線維しゅの１例

In this paper, a 16 year old male case of odontogenic myxofibroma with peculiar calcareous substances in the lower left molar region and mandibular ramus was reported. He had suffered from a swelling without pain in this region. Radiographic examination revealed a multilocular and radiolucent lesion containing a mandibular third molar and uncertain cloudy radiopaque shadows. Boundary of the lesion was radiographically comparatively clear. Extraction of the second molar and removal of the tumor were performed under general anesthesia. The tumor was 6.5×3. 5×4.0cm in size, trancelucent and light brown color, smooth surfaced with soft consistency and cystic lumens containing viscoid fluid.Thin calcareous substances were scattered in the tumor.Microscopically, the tumor consisted of dense fibrous connective and myxomatous tissues. Tumor cells were stellate or spindle shaped, but mitotic figure was not seen. The tumor contained numerous peculiar calcareous substances which varied in size and were of unknown origin. The tumor was diagnosed odontogenic myxofibroma because of the existence of epithelial islands of odontogenic origin and continuation between dental sac of the embedded third molar and tumor tissue. No recurring after treatment.

An odontogenic myxofibroma related to an embedded third molar of the mandible: Report of a case

A case of odontogenic myxofibroma involving the angle of the mandible is reported. This case arose in the area closely associated with the pericoronal portion of the embedded third molar. When the mandible resected was histopathologically examined, the tumor mass containing various shapes of epithelial cell nests and amorphous calcified bodies in the myxomatous fibrous tissue was found to be formed in the localized area well-demarcated by the enamel of the embedded tooth. These findings strongly suggest that this lesion is of odontogenic origin.

Giant odontogenic myxofibroma: Report of a case with histochemical and ultrastructural studies and a review of the literature

A case of myxofibroma of the maxilla is presented, the first to be published with electron microscopic studies. Our histochemical studies prove that the characteristic myoxid matrix is an acid mucopolysaccharide of connective tissue origin, and support the concept that this tumor arises from odontogenic tissues. The electron microscopic studies prove that the proliferating cell in this neoplasm is the fibroblast. These fibroblasts are synthesizing the mucopolysaccharide matrix, and are producing and resorbing collagen. This neoplasm is thus basically a fibroma, with the synthesis of abundant acid mucopolysaccharide by the fibroblasts giving it its characteristic myxoid appearance.