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At least 19 recordsLinked to original sources
PubMed2002

Ki-67 expression in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising from dental cysts.

This study investigated whether or not an ameloblastoma developing in the wall of a dentigerous cyst is a distinct lesion from the unicystic ameloblastoma. An immunohistochemical evaluation of Ki-67 in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising in dentigerous cysts was done. The values of Ki-67 positivity were 3.14 for the dentigerous cyst, between 5.32 and 16.56 for unicystic ameloblastoma, and 11.77 for ameloblastoma arising in a dentigerous cyst. Statistically significant differences were found between the dentigerous cyst and the unicystic ameloblastoma and between the dentigerous cyst and the ameloblastoma arising from a dentigerous cyst. No statistically significant difference was present between unicystic ameloblastoma and ameloblastoma arising from dentigerous cyst. These immunohistochemical data confirm the hypothesis that an ameloblastoma arising from a dentigerous cyst has a similar biological behavior to the unicystic ameloblastoma and should be considered as merely a histologic variant.

Adult↗
PubMed1983

The relationship of plexiform unicystic ameloblastoma to conventional ameloblastoma.

The term plexiform unicystic ameloblastoma refers to a pattern of epithelial proliferation that has been described in cystic lesions of the jaws. It has been considered hyperplastic epithelium, rather than ameloblastoma, by some pathologists because it does not exhibit previously accepted histologic criteria for ameloblastoma. This article provides histologic evidence that plexiform unicystic ameloblastoma is, in fact, a variant of conventional unicystic ameloblastoma by reporting ten cases of unicystic ameloblastoma that exhibit both patterns. Further evidence of the ameloblastomatous nature of plexiform unicystic ameloblastomas is that their biologic behavior, even when this pattern occurs alone, is similar to that of conventional unicystic ameloblastoma.

Adolescent↗
PubMed2005

Desmoplastic ameloblastoma featuring basal cell ameloblastoma: a case report.

The desmoplastic ameloblastoma is a histological variant of ameloblastoma. The neoplastic epithelial islands seen in desmoplastic ameloblastoma are small and ameloblastic cells are rare. Basal cell ameloblastoma is also a rare variant of ameloblastoma, in which the tumor is composed of more primitive cells and has even fewer features of peripheral palisading. This report describes the case of a 17-year-old female with an ameloblastoma in the right anterior maxilla. Orthopantomography and computed tomography showed a well-defined lesion in the right maxilla. A partial maxillectomy for tumor resection was performed under general anesthesia. Histologically, ameloblastic tumor cells were seen with dense collagenous stroma and the tumor cells showed primarily basal cell variants of ameloblastoma. After 7 years of follow-up, clinical and radiographic examinations have revealed no evidences of recurrence.

Adolescent↗
PubMedDate not supplied

Ameloblastoma of the maxilla and peripheral ameloblastomas.

Ameloblastomas arising in the supraperiosteal soft tissues (peripheral ameloblastoma) and those taking origin in the maxilla have distinctively different biologic behaviors. The peripheral ameloblastoma can be successfully treated by conservative excision while en bloc resection is warranted for the maxillary ameloblastoma. The effectiveness of primary surgical treatment of an ameloblastoma of the maxilla is the key to reduce morbidity and mortality from the lesion. Anatomic differences between the maxilla and mandible and an apparent more aggressive behavior of maxillary tumors also play a role in establishing the ameloblastoma of the maxilla as the most dangerous of the ameloblastomas.

Ameloblastoma↗
PubMed1984

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.

Adolescent↗
PubMed2001

Desmoplastic ameloblastoma (including "hybrid" lesion of ameloblastoma). Biological profile based on 100 cases from the literature and own files.

The profile of the desmoplastic ameloblastoma (DA) is presented, based on a survey of 100 cases. DA is a benign, locally invasive variant of the intraosseous, infiltrative ameloblastoma (IA). Radiologically, the DA shows ill-defined borders with a soap bubble appearance. The finding of a mixed radiolucency-radiopacity in 52% of the cases often leads to a preoperative diagnosis of a fibro-osseous lesion. Association with an unerupted tooth is not a typical finding. The DA accounts for 4-13% of all ameloblastomas. The over-all average age is 42.9 years, higher for males (45.9 years) than for females (39.7 years). Thus, the DA occurs at a slightly higher age than the intraosseous ameloblastoma (37.4 years). The male/female ratio is 1:1. The maxilla/mandible ratio is 1/0.9 as opposed to 1/5.4 for the IA. Seven maxillary tumours involved an entire quadrant and 15 maxillary and mandibular tumours crossed the midline of the jaws. Pathogenetically, it seems that the DA is derived from the same sources as the IA, and extra-osseous sources do not seem to play a role. Histologically, the DA reveals the following morphological characteristics: the odontogenic epithelium occurs as irregular, stellate or follicular islands and cords, the center often appearing hypercellular with spindle-shaped or squamatoid cells. Peripheral columnar or cuboidal cells rarely reveal an ameloblast-like appearance. Thus, there are only vague tendencies to mimic a follicular ameloblastoma with acanthomatous features. The most striking feature separating the DA from IA is to be found in the tumour stroma: in DA there is extensive stromal desmoplasia with an abundance of thick collagen fibres that seem to compress the epithelial islands. Nine cases of so-called "hybrid lesion of ameloblastoma" where areas of IA coexist with areas of DA are surveyed in addition to the 100 cases of DA. No conclusions can be drawn about the biological profile of this variant due to the insufficient number of cases.

Adult↗
PubMed2005

Ameloblastoma induces osteoclastogenesis: a possible role of ameloblastoma in expanding in the bone.

Ameloblastoma, a tumor located in bone, when neglected, can perforate the bone and, ultimately, spread into the soft tissues. To expand in the bone, ameloblastoma must have a mechanism of resorbing the surrounding bone. However, the mechanism for bone resorption is poorly understood. In the present study, we found that RANKL and TNFalpha were expressed and secreted by ameloblastoma cells, and was proven to induce osteoclastogenesis. Our present results also showed that phosphorylation of p38, SAPK, p44/42 and Akt were upregulated under treatment of 10xCM (concentrated conditioned media of AM-1 cells). We also noticed formation of resorption lacunae on dentin slice by 10xCM-induced osteoclast-like MNCs. These results suggested that ameloblastoma by secreting RANKL and TNFalpha could induce osteoclastogenesis.

Ameloblastoma↗
PubMed1989

Granular cell odontogenic cyst: a unicystic ameloblastoma with late recurrence as follicular ameloblastoma.

This report is a follow-up of the original case of granular cell odontogenic cyst described by Gold and Christ in 1970. The lesion, originally treated by enucleation in 1965, recurred 18 years later as a follicular ameloblastoma with prominent plexiform and acanthomatous histologic patterns. No histologic evidence of granular cells was noted in the recurrent lesion. The recurrent ameloblastoma was treated by marginal resection of the body of the mandible and immediate reconstruction with an iliac bone graft. The anatomic restoration was excellent, and there is no recurrence 5 years postoperatively. This case supports the view that the granular cell odontogenic cyst is a unicystic (monocystic) granular cell ameloblastoma, and that the presence of granular cells in ameloblastoma is not a permanent feature and may be of little value as a prognostic indicator of aggressiveness.

Ameloblastoma↗
PubMed2001

Atypical plexiform ameloblastoma with dentinoid: adenoid ameloblastoma with dentinoid.

In this study, we report a tumor that resembled previously reported uncommon tumors histologically similar to ameloblastoma or adenomatoid odontogenic tumor (AOT), showing the formation of hard tissue. We evaluated the histological characteristics by reviewing the literature. The patient was a 19-year old male. The lesion was located from the canine to third molar in the right mandible and was unicystic with a comparatively clear demarcation. The tumor tissue was cystic overall, showing multiple formation of small and large cysts. The tumor tissue resembled a variant form of plexiform ameloblastoma. Formation of dentin and dentinoid was observed in the tumor stroma, whereas formation of enamel was not observed. Very few cases of a variant form of ameloblastoma that shows formation of dentinoid have been reported, and the histological picture in this study closely resembled previously reported "adenoid ameloblastoma with dentinoid".

Adult↗
PubMed1995

Immunohistochemical localization of fibroblast growth factor-1 (FGF-1) and FGF-2 in cultured human ameloblastoma epithelial cells and ameloblastoma tissues.

Fibroblast growth factor-1 (FGF-1) and FGF-2 are mitogenic polypeptides that may contribute to neoplastic cell proliferation. In the present study, we established a serum-free culture system for ameloblastoma cells and demonstrated that the addition of FGF-1 and FGF-2 enhanced cell growth in a dose-dependent manner. Immunoperoxidase staining of cultured cells demonstrated strong expression of FGF-1 and FGF-2. In tissue specimens, FGF-1 was localized in epithelial cell components of ameloblastomas, whereas FGF-2 was mainly found in the basement membranes with only moderate staining in epithelium. These data suggest that both FGF-1 and FGF-2 may contribute to the growth and development of ameloblastomas.

Adolescent↗
PubMed1993

'Combined ameloblastoma and odontogenic keratocyst' or 'keratinising ameloblastoma'.

Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.

Adult↗
PubMed1982

Ameloblastoma and keratinizing ameloblastoma in dogs.

Ameloblastomas reviewed in this report were locally invasive neoplasms arising from the epithelial structures of the dental lamina, and were characterized histologically by features which are unique to dental lamina epithelium. These include the formation of epithelial sheets in which the cells nearest the stroma form a palisading row aligned perpendicularly to the basement membrane and the cells toward the center separate from each other except at desmosomal attachments. This is similar to the appearance of th stellate reticulum of the early enamel organ. Other features include epithelial cords which branch and interconnect, and the intimate association of epithelial structures and collagenous matrix. In our dogs, other important features were the deposition of inclusions similar in appearance to enamel matrix between the cells of the epithelium and various degrees of keratinization. All ameloblastomas studied were locally invasive tumors which occurred at various sites on the gingiva. The average age of the dogs was 8.7 years and the age range was three to 13 years. Radiographically, all of the tumors studied resulted in periodontal osteolysis. Six dogs were treated with radiation therapy, but details of the radiotherapy of two dogs could not be located. Of the other four dogs, one is alive 48 months after radiotherapy with no evidence of tumor regrowth. Regrowth of the oral tumor was apparent in the other three dogs six, 21, and 34 months after completion of the radiotherapy. Three dogs were treated by radical mandibulectomy; all are alive with no evidence of tumor recurrence at two, 20, and 28 months postoperatively. Two dogs had local dissection (curettage) of tumors and the tumors recurred at 12 and 15 months after surgery. One dog was euthanatized after diagnosis of the oral tumor because of a progressive neuropathy.

Ameloblastoma↗
PubMed1995

Ameloblastoma: biological profile of 3677 cases.

Available literature on ameloblastoma of the jaw was reviewed, including publications from 1960 to 1993, and compared to the latest larger review, published by Small and Waldron in 1955. The average age of patients with ameloblastoma is 36 years. In developing countries ameloblastomas occur in younger patients. Men and women are equally affected. Women are 4 years younger than men when ameloblastomas first occur, and the tumours appear to be larger in females. Dominant clinical symptoms such as painless swelling and slow growth are non-characteristic. The ratio of ameloblastoma of the mandible to maxilla is 5 to 1. Ameloblastomas of the mandible occur 12 years earlier than those of the maxilla. Ameloblastomas occur most frequently in the molar region of the mandible. In Blacks, ameloblastomas occur more frequently in the anterior region of the jaws. Radiologically, 50% of ameloblastomas appear as multilocular radiolucent lesions with sharp delineation. Histologically, one-third are plexiform, one-third follicular; other variants such as acanthomatous ameloblastoma occur in older patients. Two percent of ameloblastomas are peripheral tumours. Unicystic ameloblastomas occurring in younger patients have been found in 6%. Detailed data on 345 patients with ameloblastoma were evaluated for clarification of therapeutic approaches. Chemotherapy and radiation seem to be contraindicated. Ameloblastomas of the maxilla should be treated as radically as possible, ameloblastomas of the mandible should also be treated radically. However, ameloblastomas which radiologically appear as unilocular lesions may be treated conservatively (enucleation, curettage), whenever all areas of the cystic lumen are controllable intraoperatively. Unicystic ameloblastomas occurring in patients 15 years younger than those with multisystic ameloblastoma may be treated conservatively except in cases with invasion of epithelium into the cyst wall. Different recurrence rates have been found for histological variants of the ameloblastoma. Follicular ameloblastomas appear to recur more often than the plexiform type. Unicystic ameloblastomas reveal lower recurrence rates than "non-unicystic" ameloblastomas. The peripheral type of ameloblastoma may be excised, since conservative therapy results in low recurrence rates. Postoperative follow-up is most important in the therapy of ameloblastoma, because more than 50% of all recurrences occur within 5 years postoperatively.

Adolescent↗