Mandibular ameloblastoma

Ameloblastoma is an uncommon invasive mandibular tumor usually occurring as a painless enlargement of the jaw. Radiologic evidence of a multilocular lesion requires biopsy for histopathologic distinction. With its propensity for recurrence, en bloc resection of the tumor is recommended. Careful and meticulous follow-up for an extended period is necessary.

Ameloblastoma accompanied by prominent bone formation

A case of ameloblastoma accompanied by prominent bone formation is described. Although the clinical and radiographic appearance suggested an ossifying fibroma or fibrous dysplasia, microscopic examination showed an ameloblastoma of the follicular type with prominent bone formation.

A clinicopathologic study of ameloblastoma

One hundred four ameloblastomas, 97 in the mandible, five in the maxilla, and two in peripheral locations, were studied. A consistent correlation between the age of the patient and the radiographic or histologic type of mandibular ameloblastoma was observed. There was a tendency for ameloblastomas of the follicular type to show a multilocular or soap bubble appearance and for those of the plexiform type to show a unilocular appearance. Recurrent ameloblastomas had a predominantly multilocular appearance. Histologically, the ameloblastomas in the maxilla were of the follicular type.

Primary adamantinoma of rib: thoracic manifestations of a rare bone tumor

Adamantinoma is a rare tumor of long bone that has not previously been reported to involve primarily the chest wall. We have described a patient who had primary adamantinoma of the rib and who showed a spectrum of pleuropulmonary manifestations of this uncommon neoplasm.

A radiolucent lesion adjacent to the roots of the mandibular right first and second premolars

A distinct odontogenic cyst of developmental origin, the lateral periodontal cyst has characteristic clinical, radiographic, and histopathologic findings. In addition to inflammatory lesions, lateral periodontal cysts may appear similar radiographically to an ameloblastoma or odontogenic keratocyst in its early stage; therefore, clinical and histologic correlations are necessary to establish the diagnosis and ensure proper treatment.

Mandibular ameloblastoma with intracranial extension and distant metastasis

A case of mandibular ameloblastoma which invaded intracranially through the skull base and developed distant metastasis to the femur is reported. The intracranial extension of the tumor was partially removed three times and the metastasis of the femur was curetted. The remaining tumor temporarily responded to chemotherapy, but the patient died of intracranial tumor regrowth. The period from the initial treatment of the mandibular tumor to death was 21 years.

Cystic ameloblastoma. A clinicopathologic analysis

Thirty-three cases of ameloblastoma arising from odontogenic cyst linings are presented. Lesions of this nature have been referred to as "unicystic ameloblastoma." Our data support the findings of others in that this lesion differs from the solid invasive varieties of ameloblastoma, as the former occurs in a younger age group and exhibits a low rate of recurrence following enucleation or curettage. On the basis of histopathologic features we provide evidence that these lesions represent mural and luminal ameloblastomatous change in a pre-existing cyst rather than cystic degeneration of a solid tumor.

Biology of metastasizing ameloblastoma

The present report of a malignant metastasizing ameloblastoma and a critical review of literature was undertaken in an attempt to better understand the biological potential and behavior of this rare tumor and thus to facilitate its clinical management. Most of the 26 patients with a proven malignant ameloblastoma including the present case had developed multiple recurrences. The lung was the most frequent metastatic site (88%) followed by regional lymph nodes (27%). Furthermore metastases were observed in some cases in the bone, brain, kidney, small intestine and liver. The interval between diagnosis of tumor and manifestation of metastases was long with a median of 11.1 years. The average survival time was 13.1 years. By contrast, the interval between diagnosis of metastatic disease and death was relatively short (median: 2.6 years). The histologic and cytologic pattern of malignant ameloblastoma and of its metastases was not significantly different from that of non-metastatic ameloblastoma. Because of the lack of morphological criteria of malignancy the biological behavior of ameloblastomas cannot be predicted. It is difficult to be certain which factors are important in the delayed induction of metastases. It is suspected that ameloblastomas possess an inherent low grade malignancy which is stimulated by multiple recurrences. It is further assumed that the metastatic tumor cells have a slow growth rate resulting in late clinical manifestation of metastases. When lung metastases occur we recommend their surgical removal in order to prolong live expectancy or even to obtain a curative effect.

Computed tomography in the diagnosis and treatment of mandibular ameloblastoma: report of cases

Treatment of ameloblastoma is based on clinical manifestations and radiological features. The value of routine radiographs in determining the extent of the lesion may be limited. Four cases of mandibular ameloblastoma were studied using axial and coronal computed tomography (CT). The soft-tissue mass, destruction of cortical bone, and extension of tumor into the infratemporal fossa and adjacent structures were clearly visualized. These features demonstrate the superiority of CT over conventional radiography in delineating the extent of the lesion, which may be essential to its management.

Ameloblastomas of the jaws: radiological diagnosis and follow-up

Eleven of 57 tumours and cysts (19 per cent) seen at two major centres over a 4-year period were ameloblastomas, primary in eight and recurrent in three. Computed Tomography (CT) was the most sensitive imaging technique for detecting ameloblastomas. The radiological features were distinctive maxillary and mandibular pathology in primary cases and soft-tissue, maxillary sinus and asymmetrical deep tissue involvement in both primary and recurrent ameloblastomas. Following surgery and pathological confirmation, serial scans were combined with periodic clinical re-evaluation. We identified clinically occult recurrences in two cases and confirmed a clinically-suspected recurrence in one on the basis of the CT findings. Our protocol appears efficacious and is suggested for the necessary long-term follow-up in all pathologically verified ameloblastomas.

Maxillary ameloblastoma with orbital invasion. A clinicopathologic study

A 72-year-old white man presented to Massachusetts Eye and Ear Infirmary with proptosis of the right eye. Computerized tomography (CT) scan revealed a mass which filled the right maxillary sinus and invaded the orbital and middle cranial cavities. Six years earlier, the patient had excision of an ameloblastoma of the right maxillary antrum. The tumor recurred, requiring maxillectomy, local radiotherapy and finally exenteration. Ameloblastoma is a relatively rare epithelial tumor arising from embryonal tooth elements. It is locally invasive and recurrent but rarely metastasizes and extension to the orbit is extremely unusual. The clinical features, histopathologic findings and treatment of this tumor are discussed. Differential diagnosis of jaw tumors, which may invade the orbit, is reviewed.

Plexiform ameloblastoma of the maxilla with extension to the skull base

Ameloblastomas are locally invasive benign tumors believed to originate from the developing dental lamina. Maxillary ameloblastomas are rare, comprising only 20% of all ameloblastomas. Of these, 90% arise posterior to the canine tooth. As tumors of the posterior maxilla grow slowly, symptoms are few until the tumor has reached considerable size. At the time of presentation there may be evidence of extension into anatomic areas adjacent to the posterior maxilla. Hemimaxillectomy through wide surgical exposure has the best chance of achieving tumor control. However, once the tumor has extended beyond the confines of the maxilla the prognosis for control of the disease is poor.

Intrabony ameloblastoma of the jaws. An analysis of 147 Thai patients

In this study, 147 cases of intrabony ameloblastoma from the files of our departments were reviewed. Clinical findings showed an average age of 31.6 years and a sex ratio of 1.1:1. The average duration of the tumour was 2.7 years. The majority of the tumours, 93.9%, occurred in the mandible with 36.1% of the cases found in the molar area. Radiographically, 62.7% of the lesions were polycystic. Histopathologically, 49.0% had a follicular pattern. There seems to be no direct correlation between the histologic patterns and the radiographic appearances of the tumors but there is a slight indication that both monocystic and polycystic types tend to have the plexiform pattern, while the soap-bubble type tends to have the follicular pattern.

Radiographic characteristics of cystogenic ameloblastoma

Radiographic patterns encountered in mandibular cystogenic ameloblastoma, a variant encountered among teen-agers and young adults, are described and correlated with age and recurrence after surgery. More than 75% of the cases are located in the posterior mandibular ramus area, and 50% are associated with an impacted third molar. The predominant radiographic patterns include unilocular and scalloped or macromultilocular pericoronal , interradicular , or periapical expansile radiolucencies.

Plexiform unicystic ameloblastoma. A variant of ameloblastoma with a low-recurrence rate after enucleation

The term, plexiform unicystic ameloblastoma, refers to a pattern of epithelial proliferation that has been described in dentigerous cysts, primarily in persons in the second and third decades of life and predominantly in the posterior part of the mandible. This article provides the first study on the biologic behavior of these lesions. Of 28 examples treated by enucleation/curettage, and for which adequate follow-up information was obtained, only three recurred. This figure (10.7%) compares very favorably with the 55% to 90% recurrence rate quoted for ameloblastomas of all types that have been treated by curettage and is similar to that found in other types of unicystic ameloblastoma. The plexiform unicystic ameloblastoma is concluded from this study to be an undifferentiated histologic variant of unicystic ameloblastoma and not a separate entity. Enucleation with long-term follow-up information is adequate for tumors that have proliferated into the lumen of the cyst, but more extensive surgery is recommended for those that involve the periphery of its fibrous connective wall. This study has also shown that plexiform unicystic ameloblastomas are not always associated with unerupted teeth, in which case they probably occur over a wider age range than those resembling dentigerous cysts.

Computed tomography of mandibular ameloblastoma

Three cases of ameloblastoma of the mandible--unicystic, multicystic, and malignant types--are presented. Computed tomography (CT) may play an important role in delineating the extent of these tumors, which require extensive radical surgery. The cystic component of these lesions is well demonstrated by CT and suggestive of the diagnosis.

[Recurrent ameloblastoma of the upper jaw--diagnosis]

Ameloblastomas of the jaw are rare epithelial tumors. They have to be differentiated from simple cysts and malignant tumors. If incompletely excised they have a high recurrence rate so that radical surgery from the beginning must be the therapy of choice. Exact preoperative diagnosis of the tumor and its possible spread into the infratemporal fossa or the pterygopalatine fossa, into the parapharyngeal space, the orbit or into the intracranial space is mandatory. In this paper we present a case with recurring ameloblastoma. The value of the different diagnostic procedures is discussed.

Case report 235. Ewing-like adamantinoma of the left radial head and neck

Skeletal adamantinoma is a rare malignant bone tumor with a poorly understood histogenesis. The lesion is easily recognized by a distinctive microscopic pattern of anastomosing trabeculae of epithelial-like cells in a fibrous stroma. Ultrastructural evidence has been presented to support an origin from two widely-divergent cell types: an epithelial cell with squamous characteristics [12, 15] and a mesenchymal cell with endothelial features [5, 9]. An addition to the histogenetic controversy has been the recent description of a bone neoplasm with an adamantinoma-like growth pattern which proved both by subsequent histological evolution and ultrastructure, to have features of Ewing tumor [10]. The authors report a further example of this entity and suggest that it may be sufficiently distinctive within the adamantinoma group to merit the term Ewing-like adamantinoma. Consonant with increasing evidence supporting the concept of tumor "metaplasia" that transcends traditional concepts of epithelial-mesenchymal immutability, the authors propose that all adamantinomas arise from a common stem cell.

[Ameloblastomas of the maxilla (author's transl)]

Ameloblastomas of the maxilla usually arise in persons in the middle of their lives and do not show any predominance in sex distribution. Six case reports and a review of the literature demonstrate that the tumor mostly causes unspecific symptoms and therefore is often only diagnosed very late. In the majority of cases the initial treatment was irradiation or limited surgery, assuming that the ameloblastoma is a benign, non-metastasizing tumor. In such cases the tumor tends to recur repeatedly and the disease becomes early incurable by local growth. Therefore ameloblastomas of the maxilla have to be treated by radical surgery, usually maxillectomy, from the very beginning like malignant tumors.

Appendicular skeletal tumours coined by odontogenic terms

Two intriguing tumours in the appendicular skeleton are coined by odontogenic terms: the "adamantinomas" and "cementomas" (or "cementifying fibromas"). Both are extremely rare, mainly the latter. Eight verified observations are presented here: five adamantinomas and three cementomas. Whereas in adamantinomas, the localization and radiographic picture was very typical in all cases, only one cementoma was found in the metaphysis of a long tubular bone in our survey. Diaphyseal tibial localization in one, and metacarpal in the another patient are the first two atypical localizations, described for this tumor in the world's medical literature. Angiography is characteristic for a benign expansive lesion and should be carried out in all cases. An "en bloc" resection is the intervention of choice for both these entities.

Metastatic ameloblastoma of the skull

A rare case of a metastatic ameloblastoma of the skull in a 29-year-old woman is reported. An ameloblastoma of the left mandible underwent histological malignant transformation following repeated operations and eventually metastasized to the left temporoparietal region of the skull. The skull tumor showed osteolytic change and marked vascularity in roentgenological examinations. It was removed totally. The histological findings were similar to those of the tumor of the left mandible. The route of the metastasis was considered to be via the left external carotid artery.