Pathology of the desmoplastic ameloblastoma

Malignant Transformation of a Desmoplastic Ameloblastoma to Squamous Cell Carcinoma: A Case Report

Ameloblastomas are the most common odontogenic tumors, excluding odontomas. Several morphologic variants have been described including follicular, plexiform, acanthomatous, granular cell, basaloid and desmoplastic. Desmoplastic ameloblastoma differs from other conventional ameloblastomas microscopically, clinically, and radiographically. Ameloblastic carcinoma, the malignant counterpart of ameloblastoma is characterized by cytologic features of malignancy combined within the overall histologic features of conventional ameloblastoma. Malignant transformation of ameloblastoma to squamous cell carcinoma is a controversial subject. Here we report a case of a desmoplastic ameloblastoma with malignant transformation to squamous cell carcinoma in a 49 year old African American man. The patient underwent tumor resection and radiation therapy with no evidence of disease recurrence or progression 16 months post operatively. To our knowledge malignant transformation of a desmoplastic ameloblastoma to squamous cell carcinoma has not so far been reported. This observation may lend some support to the argument that desmoplastic ameloblastoma is phenotypically and biologically distinct entity.

Clinicopathological characteristics of desmoplastic ameloblastoma: A systematic review

The aim of the present review was to systematically present the clinicopathological data of desmoplastic ameloblastoma (DA) from articles published in the literature. A comprehensive search of the databases (PubMed, Medline, SCOPUS, Web of Science, and Google Scholar) for published articles on DA was conducted. A total of 238 cases were identified and analyzed from 76 published papers. DA showed a slight male predilection (male: female=1.07:1) with a predominance in the fourth and fifth decades of life. Mandibular involvement (52.55%) was most commonly seen with a marked tendency for the anterior region (mandible: 40.9%, maxilla: 48.07%). The size of the lesion ranged from .5 cm to 20.4 cm, with the majority of cases measuring more than 3 cm in size (53.84%). Radiologically, most of the lesions presented mixed radiolucency and radiopacity (62%), and root resorption was observed in only seven cases. The majority of the lesions showed ill-defined margins upon radiographic examination (65.78%). Most of the cases were treated with resection (78.57%), and five of the 10 recurrent cases were treated by enucleation/curettage. DA is characterized by the unique presentation of clinicopathological parameters. It is not possible to comment on its aggressive/recurrent nature and best treatment modality due to inadequate follow-up data.

A case report on desmoplastic ameloblastoma of anterior mandible

BACKGROUND

Desmoplastic ameloblastoma (DA) is a rare variant that accounts for approximately 4-13% of ameloblastoma, displaying significant differences in anatomical site, imaging, and histologic appearance. It has been included in WHO classification of head and neck tumor (WHO-2005) as a variant of ameloblastoma. The tumor resembles benign fibro-osseous lesion for being frequently occurring in the anterior region of jaws as a mixed radiopaque-radiolucent lesion.

CASE PRESENTATION

We present a case of DA in a 43-year-old female with a painless swelling in the anterior region of mandible. No fluid was evident on fine needle aspiration. A mixed lesion with multilocular appearance was evident on both panoramic radiographs as well as computed tomography scan. An incisional biopsy confirmed it to be a case of desmoplastic ameloblastoma. Segmental mandibulectomy was performed from teeth 35 to 44. The patient is on routine follow-up and is currently free of ailment.

CONCLUSIONS

The present case deserves emphasis because of its unfamiliar appearance, potentially aggressive nature and deceptive radiologic appearance maximizing the chances of misdiagnosis. So, the clinician should be alert enough to include desmoplastic ameloblastoma in differential diagnosis of any lesion/growth with mixed radiolucent-radiopaque appearance having ill-defined borders and occurring in anterior maxilla or mandible.

Peripheral desmoplastic ameloblastoma in adolescent age: clinico-pathological and immunohistochemical analisys of a case

The Extraosseous or Peripheral Ameloblastoma (PA) is a rare and benign odontogenic tumour, representing 1% to 5% of all ameloblastomas. It is usually localized in the soft oral tissues, without deep bone involvement. Its biological behaviour is specific, and several authors define PA as a non-infiltrating hamartomatous lesion. Indeed, recurrences rarely occur and progression in malignant tumors appears to be rare. The PA originates from the tooth-forming apparatus and it consists of proliferating odontogenic epithelium, exhibiting the same histological cell types and patterns of the intraosseous counterpart or infiltrating ameloblastoma. The peripheral desmoplastic ameloblastoma (PDA) can be classified as a newly recognized and very rare histological variant. To our knowledge, only a few cases of adult patients affected by PDA have been published. The aim of this paper is to report a case of PDA affecting an adolescent patient. The clinical-pathological and immunohistological features are discussed in order to improve knowledge regarding a correct diagnosis and to differentiate PDA lesions from similar diseases.

Desmoplastic ameloblastoma with osteoplasia: Review of literature with a case report

Desmoplastic ameloblastoma (DA) is a relatively rare histological variant of ameloblastoma with specific clinical, radiological, and histological features. This tumor is more commonly seen in the anterior region of jaws as a mixed radiopaque-radiolucent lesion resembling benign fibro-osseous lesions. Histologically, DA is characterized by small nests and strands of “compressed” odontogenic epithelium supported by pronounced collagenized stroma. Metaplastic bone formation has been reported in few cases. This report describes a lesion in the left anterior maxilla of a young female patient.

Desmoplastic ameloblastoma of mandible

Desmoplastic ameloblastoma is one of the six histopathological subtypes of ameloblastoma. The age and gender groups affected by desmoplastic are similar to those affected by the conventional ameloblastoma. It usually presents as a painless enlargement of the jaw. Owing to its deceptive radiological appearance as a mixed radiopaque-radiolucent lesion, it is often mistaken as a fibro-osseous lesion. Histologically, desmoplastic ameloblastoma has a densely collagenised and hypocellular stroma, where the epithelium tends to proliferate in the form of cords and nests instead of cellular islands. Most desmoplastic ameloblastomas display occasional classic islands of follicular ameloblastoma among the predominant strands and cords. Studies have shown that desmoplastic ameloblastoma shows a tendency to recur. We present a rare case of a tumour occurring in the anterior mandibular region in a 60-year-old man over a period of 11/2 months.

An unusual case of unicystic intramural ameloblastoma and review of the literature

Ameloblastoma is the most common tumor of odontogenic origin. There are various types of this tumor and confusion still exists among the clinicians about the correct classification. Multicystic ameloblastoma is the most frequent subtype while unicystic ameloblastoma can be considered as a variant of the solid or multycistic. This subtype is considered as a less aggressive tumor with a variable recurrence rate. However, its frequency is often underestimated. The aim of this article is reviewing the recent literature about unicystic ameloblastoma using our unusual clinical case as a starting point to illustrate this discussion. A 30-year-old man who had been complaining of slight pain in the premolar and molar area of the left side of mandible had a check up at our department. X-rays revealed a unilocular radiotrasparency with radiopaque margins. The first histological diagnosis was an odontogenic cyst. Successive histological evaluations revealed that ameloblastic epithelial islands were present in lassus connective tissue. We think that our case report provides new insights into the approach to the ameloblastoma diagnosis. We agree with authors who have pointed out that a single small biopsy may often be inadequate for the correct diagnosis of amelobastoma. Moreover, in the light of our experience, it should be kept in mind that ameloblastomas may have sometimes unusual presentations and this fact should induce surgeons and pathologists to consider carefully each lesion.

A case of desmoplastic ameloblastoma arising in the maxillary alveolus: the origin and time-course changes in the early stage of tumour development observed on dental radiographs

In this article we report a case of desmoplastic ameloblastoma in which chronological changes in the early development can be observed on dental radiographs. The tumour grew very slowly and did not appear to have a strong potential for local extension like typical ameloblastomas. Radiological findings of our case suggest the tumour arose from the periodontal membrane. However, it was not possible to obtain conclusive histopathological evidence.

Desmoplastic ameloblastoma: a case report

Desmoplastic ameloblastoma is a rare variant of ameloblastoma. Up until now, less than 150 patients have been reported in the literature. We report a case of desmoplastic ameloblastoma in a 45-year-old female with a painless swelling in the left anterior maxillary region. Fine needle aspiration yielded no fluid. Periapical and panoramic radiographs as well as computer tomography scan showed a mixed lesion with multilocular appearance. The present case deserves special importance be-cause of its unfamiliar appearance, potentially aggressive nature and high chances of misdiagnosis. Moreover, the radio-graphic features of this lesion rarely point towards ameloblastoma. A partial maxillectomy for tumor resection was per-formed and the involved teeth were removed. This report is an attempt to help the dental community in developing familiarity with the clinical presentation and at the same time advocating to develop a high index of suspicion in recognizing such cases.

Desmoplastic ameloblastoma

Ameloblastoma is a rare benign odontogenic epithelial tumor characterized by abnormal cell growth, which easily infiltrates and destroys surrounding bony tissues. Clinically, it is mostly seen in the ascending ramus area, in men in their fourth and fifth decades more frequently than in women. One of the 3 clinical variants of ameloblastoma is desmoplastic type, with involvement of the maxillary arch more often than the mandible. Its histopathologic variant characterized by extensive squamous metaplasia, islands of tumor cells, and sometimes keratin formation is known as desmoplastic acanthomatous ameloblastoma.The aim of this report was to present an unusual case of symphysis located desmoplastic acanthomatous ameloblastoma in a 56-year-old female patient, who was experiencing laryngeal carcinoma 2 years ago.

Desmoplastic ameloblastoma - A review

Among the ameloblastomas, the desmoplastic variation is rare. The desmoplastic ameloblastoma (DA) is characterized by specific clinical, imaging, and histological features. The here presented retrospective analysis investigated the clinicoradiographic features of an overall of 115 DA-cases, having been reported in literature from 1984 to 2008. DA showed a nearly equal male to female ratio (55/59) with a prevalence within the forth and fifth decades. Sixty-two lesions occurred in the mandible and fifty-one lesions in the maxilla. Clinically, a painless swelling with buccal extension was the most common presentation being found in 48 cases. Radiologically, the lesion often presented multilocular (49.3%; 36/73), mixed radiolucent/radiopaque (55.6%; 50/90) and with ill-defined borders (64.0%; 48/75). Whereas enucleation provided a recurrence rate of 21.1%, resection reduced this rate remarkably to 3.1%. The average period until recurrence was 36.9 months. Histologically, scattered epithelial nests and extensively desmoplasia were prominent features of DA. In conclusion, these retrospective results confirm the statement that DA is a variation among ameloblastomas. DA present clinicoradiographic and histologic distinct features, when compared with "conventional ameloblastomas".

Peripheral desmoplastic ameloblastoma: report of a case and literature review

The desmoplastic variant of ameloblastoma is a rare, locally invasive, benign tumor of the jaws, typically found in the anterior regions of the maxilla and mandible. This ameloblastoma variant has been described as an intraosseous tumor; to our knowledge, there have been no published cases of a peripheral desmoplastic ameloblastoma. The purpose of this case report is to describe a patient with a desmoplastic ameloblastoma localized to the soft tissue of the palate with no osseous involvement.

"Hybrid" lesion of desmoplastic and conventional ameloblastoma: immunohistochemical aspects

Ameloblastoma is a benign epithelial odontogenic tumor and is the most commonly encountered odontogenic tumor in the jaws. Histologically, ameloblastomas occur in different patterns, including plexiform pattern and follicular pattern. "Hybrid" lesion of ameloblastoma is a tumor variant in which histologically, areas of follicular or plexiform ameloblastoma coexist with characteristic areas of ameloblastoma exhibiting pronounced stromal desmoplasia (desmoplastic ameloblastoma). The purpose of this article is to present a case of "hybrid" lesion of desmoplastic ameloblastoma (AD) and conventional, and investigate extracellular matrix proteins such as tenascin, fibronectin, and type I collagen.

Caracterização imuno-histoquímica de lesão híbrida de ameloblastoma desmoplásico e convencional

O ameloblastoma é uma neoplasia odontogênica benigna comumente encontrada nos ossos maxilares. Histologicamente, mostra diversos padrões, incluindo a ameloblastoma plexiforme e folicular. Quando estes padrões histológicos coexistem com um ameloblastoma que exibe abundante desmoplasia, são então denominados de lesão ‘híbrida" de ameloblastoma desmoplásico e convencional. No presente trabalho, nos propomos a relatar um caso de lesão híbrida de ameloblastoma desmoplásico e convencional destacando os aspectos imuno-histoquímicos relativos a expressão das proteínas da matriz extracelular (tenascina, fibronectina e colágeno I).