Desmoplastic Ameloblastoma Research Articles

下顎骨に生じた広範な線維形成性エナメル上皮腫の１例

We describe a large desmoplastic ameloblastoma occurring in the mandible. Clinical and radiographic examinations 2 years after surgery revealed no evidence of recurrence, and good continuity of the mandible was reestablished.

下顎骨前歯部に生じたｄｅｓｍｏｐｌａｓｔｉｃ ａｍｅｌｏｂｌａｓｔｏｍａの１例

A case of desmoplastic ameloblastoma is reported. The patient was a 77-year-old woman, who visited our hospital because of painless expansion of the anterior region of the mandible. Radiograms and CT scans revealed a mixed radiolucent-radiopaque lesion, which was poorly defined and associated with large cystic radiolucent areas. The lesion was excised, followed by the curettage of the underlining intact bone, under general anesthesia. Histologically, the lesion was composed of enamel organ-like tumor nests scattered in prominent fibrous connective tissue. Some tumor nests showed microcyst formation and transition to larger cysts. TGF-β was strongly expressed especially by tumor cells at the periphery of tumor nests, unlike conventional types of ameloblastomas. The postoperative course has been uneventful for 6 months. Clinical and radiographic characteristics of this tumor are discussed.

Immunoexpression of transforming growth factor beta in desmoplastic ameloblastoma.

Desmoplastic ameloblastoma (DA) is an unusual subtype of ameloblastoma histologically characterized by the pronounced collagenized stroma. In the present study, the immunolocalization of transforming growth factor beta (TGF-beta), one of the most potent local factors for modulating extracellular matrix formation, was observed in DA in order to study its participation in the stromal desmoplasia. Seven cases of DA, including a "hybrid" lesion, were studied together with ten cases of ordinary follicular and plexiform ameloblastomas as the control. In contrast to ordinary ameloblastomas, marked immunoexpression was observed in all DAs but one. In the "hybrid" lesion, TGF-beta was not expressed in the area of follicular ameloblastoma but in that of DA. These results show that TGF-beta produced by tumor cells of DA plays a part in the desmoplastic matrix formation.

A unique case of desmoplastic ameloblastoma of the mandible: Report of a case and brief review of the English language literature

A unique case of desmoplastic ameloblastoma is reported from the clinical, radiographic, and histologic viewpoints. The patient was a 56-year-old man who complained of a painless swelling on the buccal aspect of the left mandible. Periapical and panoramic radiographs revealed a rounded, slightly radiolucent area with blurred osteosclerotic margins. Occlusal radiograph and computed tomography images disclosed buccal bone expansion outlined by thinned cortices. Computed tomography images exhibited an enhanced area in the anterior portion of the lesion. Interestingly, the coronal computed tomography images revealed a close relationship between the periodontal membrane of the left mandibular second premolar and the enhanced area. Biopsy specimens from the anterior portion of the lesion displayed typical histologic features of the desmoplastic variant of ameloblastoma. However, those from the posterior portion disclosed a large cystic formation. Oxytalan fibers were identified in the stromal tissue of the tumor, which suggested that the tumor arose from the epithelial rests of Malassez in the periodontal membrane of the related tooth. We also reviewed previously reported 41 cases. In 36 of 38 cases in which the location was specified, the tumor was found in the anterior to premolar region of the maxilla or mandible. A radiographic description was given in only 29 previous cases, 28 of which involved multilocular lesions. No cyst as large as the one in the present case was found among the previously reported desmoplastic ameloblastomas. Although the present case deviates from the usual desmoplastic variant of ameloblastoma in terms of locus, radiologic appearance, and cyst formation, it still meets the histologic criteria for this variant in both the stromal and epithelial components. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:258-63)

Clinical and Histopathological Analyses of Desmoplastic Ameloblastoma

Desmoplastic ameloblastoma (DA) is an unusual subtype of ameloblastoma characterized by pronounced desmoplastic stroma. There is, however, still argument whether DA is a distinct clinicopathologic entity. To enhance knowledge of DA, 7 cases of DA (7.9%) were retrieved from 89 ameloblastomas field in the Department of Oral Pathology, Hiroshima University School of Dentistry and analyzed clinicopathologically and histopathologically. The mean age of the patients with DA and non-DA at the time of the diagnosis was 40.6 +/- 5.9 years and 33.1 +/- 2.0 years, respectively. The male-to-female ratio was 2.5:1 in DA and 1.8:1 in non-DA. Four (57%) DAs were located in the maxilla where only 6% of the non-DA occurred. Interestingly, all DAs arose in the anterior/premolar area of the jaws and 6 cases were located mainly within the alveolus. None of the DA showed typical radiographic features of ameloblastoma. In 5 DAs, scattered radiopacities were observed in the radiolucent lesion and gave preoperative diagnoses of non-ameloblastomatous lesions or even osteosarcoma. All DAs showed pronounced desmoplastic stroma where there were compressed tumor islands usually lacking a peripheral layer of ameloblastic cells and a central zone of stellate reticulum. There was cystic change within the epithelial nests in 3 DAs and true glandular structures with mucus cells in a case of DA. Tumor islands often infiltrated into marrow spaces of surrounding bone. There was no capsule formation. Recurrence rate was 14% in DA and 20% in non-DA. The present study based on data of DA in the Japanese population supports that DA must be considered as a distinct clinicopathologic entity.

A Case of Desmoplastic Ameloblastoma of Mandible in Elderly Patient

A Case of Desmoplastic Ameloblastoma of Mandible in Elderly Patient

Desmoplastic variant of ameloblastoma in Chinese patients

Desmoplastic ameloblastoma is a rare tumour, and we know of only 43 previously reported cases. We report seven Chinese patients (five men and two women) with the desmoplastic variant of ameloblastoma, which makes up 9% of all ameloblastomas diagnosed during the years 1981–1995. The age ranged from 18 to 68 years (mean 43). Five of the tumours were in the maxilla and two were in the mandible. Five of them were situated anteriorly, the remaining two cases involving both anterior and posterior maxilla. The features of the 42 cases previously reported were reviewed and were compared with those in the present study. Our results differ in that we found a male predominance, wider age range and more tumours in the maxilla. Histologically, this variant of ameloblastoma is characterized by abundant collagenous stroma. Because the epithelial clusters may show prominent squamous metaplasia or may be compressed into thin strands in most areas, the appearance may mimic a squamous odontogenic tumour or odontogenic fibroma. The behaviour of this variant of ameloblastoma is likely to be the same as that of the classic ameloblastoma.

Desmoplastic Ameloblastoma in the Mandible: Report of a case with an immunohistochemical study of epithelial cell markers.

A rare case of desmoplastic ameloblastoma is presented with an immunohistochemical study of epithelial cell markers. A 42-year-old Japanese woman was admitted with a complaint of painless swelling in the anterior mandible. Radiological examination revealed an ill-defined lesion with a mixed radiolucent-radiopaque appearance. Tumor extirpation was performed, and no sign of recurrence has been confirmed. Histological examination exhibited proliferative epithelial islands surrounded by extensive dense fibrous connective tissue stroma. Most of the tumor cells lacked ameloblastic cellular polarization. The tumor cells showed positive immunoreactivities for anti-cytokeratin 8, 13 and 19, filaggrin and ameloblastoma antibodies, retaining the odontogenic epithelial characteristics.

上顎前歯部に発生した線維形成性エナメル上皮腫の１例

Desmoplastic ameloblastoma is a rare histologic variant of ameloblastoma. This tumor is unique in forming abundant collagenous stroma with small nests or strands of odontogenic epithelium.In this paper, we report a case of desmoplastic ameloblastoma arising in the anterior maxilla of a 64-year-old woman. Radiological examination revealed unicystic maxillary bone resorption with an ill-defined border. The tumor and regional maxillary bone were excised. The tumor measured 24×22×19mm, and the cut surface showed a solid mass containing a cystic space. Microscopically, proliferation of basal-cell-like odontogenic epithelial cells scattered in a mature fibrous stroma was noted. The related literature is discussed.

下顎前歯部に発生した線維形成性エナメル上皮腫の１例

We report a case of desmoplastic ameloblastoma in the anterior region of the mandible. The patient was a 44-year-old woman presenting with swelling of the anterior region of the mandible. X-ray examination showed root separation a 3 1 2 1, a cylindroid radiolucent area under the root of 2 + 2, and a honeycomb appearance around this cystic region. A benign tumor was diagnosed clinically, and complete excision was performed with the patient under general anesthesia.Histopathological examination of the surgical specimen showed a follicular type ameloblastoma with a cystic region and a desmoplastic region. Pathologically, The diagnosis was a hybrid type ameloblastoma.There has been no evidence of recurrence as of 16 months after the operation.

Some current concepts on the pathology of ameloblastomas

This article describes some fundamental concepts and new developments in the pathologic characteristics of ameloblastoma. The former include (1) the necessity of separating ameloblastomas into three clinical types, namely the solid or multicystic (the classic intraosseous ameloblastoma), the unicystic, and peripheral varieties; (2) the importance of the tumor's location in the jaws; and (3) the manner in which cancellous and compact bone of the jaws affect the spread of ameloblastomas. New developments discussed include the desmoplastic ameloblastoma, the clear cell ameloblastoma, the recognition of the so-called acanthomatous epulis in dogs as a fairly common spontaneous animal model of ameloblastoma, and some work concerning therapeutic irradiation of ameloblastomas. Additional topics include the problems involved in the early microscopic diagnosis of ameloblastoma and of ameloblastic carcinoma and our lack of knowledge concerning the cause of ameloblastomas.

Nerve damage associated with rigid internal fixation of mandibular fractures

This article describes some fundamental concepts and new developments in the pathologic characteristics of ameloblastoma. The former include (1) the necessity of separating ameloblastomas into three clinical types, namely the solid or multicystic (the classic intraosseous ameloblastoma), the unicystic, and peripheral varieties; (2) the importance of the tumor's location in the jaws; and (3) the manner in which cancellous and compact bone of the jaws effect the spread of ameloblastomas. New developments discussed include the desmoplastic ameloblastoma, the clear cell ameloblastoma, the recognition of the so-called acanthomatous epulis in dogs as a fairly common spontaneous animal model of ameloblastoma, and some work concerning therapeutic irradiation of ameloblastomas. Additional topics include the problems involved in the early microscopic diagnosis of ameloblastoma and of ameloblastic carcinoma and our lack of knowledge concerning the cause of ameloblastomas.

Infrequent clinicopathological findings in 108 ameloblastomas.

One hundred and eight ameloblastomas diagnosed in a rural black Africa population were analysed for clinicopathologic findings other than those classically described. One patient had a polycystic ameloblastoma adjacent to an ameloblastic fibroma. Two other polycystic ameloblastomas showed aneurysmal bone cyst formation and one mandibular tumour was diagnosed as a keratoameloblastoma. Microscopic changes resembling an adenomatoid odontogenic tumour were present in association with two unicystic ameloblastomas and a HPV18-positive verrucous lesion occurred in the lining of a cystic space of a polycystic ameloblastoma. Two ameloblastomas contained eosinophilic granules in all tumor cells and melanocytes were diffusely present in another. One case exhibited a focus of mucous cell metaplasia. Two polycystic ameloblastomas showed diffuse interstitial ossification. One mandibular tumor was diagnosed as a desmoplastic ameloblastoma and another as an odontoameloblastoma. This study demonstrated that although ameloblastomas are regarded as a fairly homogeneous group of neoplasms, detailed investigations prove clinicopathologic diversity in a significant number of lesions.

上顎前歯部に発生したＤｅｓｍｏｐｌａｓｔｉｃ Ａｍｅｌｏｂｌａｓｔｏｍａの１例

Desmoplastic ameloblastoma was first described by Eversole in 1984. We recently encountered a case of desmoplastic ameloblastoma in the anterior maxilla.A 52-year-old man presented to the First Department of Oral and Maxillofacial Surgery of Meikai University. A biopsy was performed, and examination of the biopsy specimen indicated a diagnosis of odontogenic fibroma. The patient underwent tooth extraction in the affected region and tumor resection under general anesthesia.Microscopic examination after the operation showed an extensive collagenized stroma containing small islets of tumor epithelium with a slight tendency to from cystic structures. The histological diagnosis was thesefore desmoplastic ameloblastoma.

Ｄｅｓｍｏｐｌａｓｔｉｃ ａｍｅｌｏｂｌａｓｔｏｍａに関する臨床的，Ｘ線学的ならびに病理学的検討

Some ameloblastomas consist of sparse small nests and strands of odontogenic epithelium associated with desmoplastic stroma. This type of ameloblastoma was designated as desmoplastic ameloblastoma in the new WHO classification of odontogenic tumors in 1992. Over the past 22 years from 1970 to 1991, we diagnosed 4 cases of desmoplastic ameloblastoma among 124 primary cases of ameloblastoma, and analyzed them clinically, radiologically and histopathologically.1. The age at the initial visit was the third decade or over. Three cases occurred in the mandible and one case in the maxilla. The incidence of desmoplastic ameloblastoma was 3.2% of all ameloblastomas in the jaw bones.2. Three cases occurred in the anterior to the first premolar region and one case in the anterior to the first molar. These tumors seemed to develop from the alveolar process.3. Radiologically, all cases showed a honeycomb appearance containing mottled or dotted radiopacities with ill-defined margins.4. Divergency of tooth roots was seen in all cases, and some roots showed prominent resorption.5. Grossly, all tumors were solid type. Histologically, small sparse nests which showed acanthomatous type, stroma containing abundant collagen fibers, and many irregularly shaped areas of lamenar bone were observed. In the irregular bone, bone resorption and formation was seen concomitantly. The tumor invaded the adjacent bone marrow.6. Marginal resection was performed in 3 cases and enucleation followed by curettage in one case. No recurrence was noted.

Desmoplastic ameloblastoma: A case report and literature review

The desmoplastic ameloblastoma is a rare histologic variant of ameloblastoma. This article presents a case of desmoplastic ameloblastoma with unique and complex histologic findings. The tumor, which was located in the anterior mandible, was treated by an anterior marginal resection with preservation of the inferior border of the mandible. The clinical, radiographic, surgical, and pathologic aspects of this unusual lesion are presented, and the relevant literature is reviewed.

Patterns of expression of intermediate filaments and S-100 protein in desmoplastic ameloblastoma.

Seventeen cases of desmoplastic ameloblastoma were examined immunohistochemically. Immunoperoxidase techniques were applied for detection of keratin, desmin, vimentin and S-100 protein expression in these tumors. The tumor epithelium of desmoplastic ameloblastoma exhibited weak, focal, inconstant keratin staining, weak, variable expression of S-100 protein, desmin immunoreactivity of mild to moderate intensity and vimentin non-reactivity. The pertinent literature on the immunohistochemistry of ameloblastomas is briefly reviewed.

上顎エナメル上皮腫の臨床統計的観察

We analyzed 10 maxillary ameloblastomas clinicostatistically for the past 23 years from 1970 to 1992. The incidence of maxillary ameloblastoma was 6. 5% of all ameloblastomas in the jaw bones. Age at the initial visit was the fifth decade or over in eight patients. Many tumors extended from the anterior or premolar to molar region and 6 cases involved the maxillary antrum. There was no case with an embedded tooth in the tumor. Radiographically, unilocular and multilocular radiolucency was seen in the majority of cases. Histologically, follicular type was seen in six cases, basal cell ameloblastoma in 3, and desmoplastic ameloblastoma in 1. Two cases of follicular type and 1 of basal cell ameloblastoma were malignant ameloblastomas. Recurrence was noted in 2 of the cases; both of these 2 cases were malignant ameloblastomas.

The desmo-and osteoplastic ameloblastoma: Histologic variant or clinicopathologic entity? Case reports

Two cases of desmoplastic ameloblastoma (DA) are presented, bringing the total number of reported cases to 29. One case of the so-called “hybrid lesion” is added to the presentation. Immunohistochemical studies indicate that the desmoplasia is caused by active de nova synthesis of extracellular matrix proteins. Moreover, the DA may also show osteoplasia, and this probably explains the characteristic radiographic appearance of many DAs, i.e. the occurrence of both radiolucent and radiopaque changes, suggestive of a fibro-osseous lesion. Many more cases of DA are needed to clarify the true nature of this most interesting tumor.