Unique odontogenic tumor with dentinogenesis and features of unicystic plexiform ameloblastoma

Diagnostic Enigma of Adenoid Ameloblastoma: Literature Review Based Evidence to Consider It as a New Sub Type of Ameloblastoma

Adenoid ameloblastoma is a hybrid odontogenic tumour showing histopathological features of both ameloblastoma and adenomatoid odontogenic tumour (AOT), with approximately 40 cases reported in the literature. The aims of the report are to illustrate the diagnostic challenges of adenoid ameloblastoma using three new cases and to analyze evidence in literature to consider adenoid ameloblastoma as a new sub type of ameloblastoma. A literature review was performed with the key words-adenoid ameloblastoma, hybrid/composite odontogenic tumours, hybrid ameloblastoma and adenomatoid odontogenic tumour, ameloblastoma with inductive changes, dentinoid and dentinoma to select the cases compatible with the diagnosis of adenoid ameloblastoma. Out of the 40 cases reported in literature, 31 cases with sufficient information and 3 new cases were analyzed. Out of the 34 adenoid ameloblastomas majority of tumours (76.5%) occurred in adults with age ranging from 25 to 55 years. Slight female predilection with a male:female ratio of 0.9:1 was observed. Approximately, 64.7% occurred in the mandible. Radiologically, 82.4% of adenoid ameloblastomas presented as radiolucent lesions while 47.1% occurred with ill-defined margins and cortical perforation at diagnosis. Histopathologically, 70.8% of tumours presented as plexiform ameloblastomas, while duct like structures/glandular structures were the commonest feature supportive of adenomatoid odontogenic tumour observed in overwhelming majority of 95.9% of adenoid ameloblastomas. 91.6% of tumours showed inductive change in the form of dentinoid. Further, 45.4% of the tumours developed at least one recurrence following surgical excision. The report presents literature review based evidence to show the existence of adenoid ameloblastoma, which is demographically similar to conventional ameloblastoma but with histopathological differences and presenting with higher rate/multiple recurrences, indicating its biological aggressiveness. Thus, we would like to propose the inclusion of adenoid ameloblastoma as a sub type of ameloblastoma in the next revision of the WHO odontogenic tumour classification.

Ameloblastoma with adenoid features: A series of eight cases

BACKGROUND

Ameloblastoma with adenoid features are characterized by the presence of duct-like structures formed from the parenchyma of the tumor. This study was conducted to report a series of eight ameloblastomas with adenoid features, highlighting their clinicopathological and immunohistochemical aspects.

MATERIAL AND METHODS

Out of 71 cases of ameloblastomas, this study classified 8 cases as ameloblastomas with adenoid features. Clinicopathological data and immunohistochemistry for CK7, CK14, CK19, IMP3, p53 and Ki-67 were evaluated.

RESULTS

From those cases of ameloblastoma exhibiting adenoid features, there were 4 women and 4 men, with mean age of 39 years. Most cases affected the mandible and all presented radiographically as a radiolucency. The predominant histopathological features were pseudoducts, squamous metaplasia, nuclear hyperchromatism, clear cells, whorled aspect of epithelial structures, cribriform growth pattern, proliferation of spindle cells and extracellular eosinophilic material. Immunohistochemical analysis showed high expression for CK14 (n = 6) and CK19 (n = 3) and all cases (n = 8) were negative for p53, IMP3 and CK7. In addition, all samples (n = 8) showed low expression for Ki-67.

CONCLUSIONS

The similarities between the histopathological and immunohistochemical features of eight cases described in the present study and those described in previous studies support the possibility that these lesions are adenoid ameloblastomas. In addition, the immunohistochemical results of CK14, CK19, p53 and Ki-67 did not differ from those of conventional ameloblastomas.

Adenoid ameloblastoma with dentinoid: A rare hybrid variant

Odontogenic tumors comprise an unusual group of lesions of the jaw and present diverse histological patterns. Derived from the primordial tooth-forming tissues, they represent a heterogeneous group of lesions that range from hamartomas to benign and malignant neoplasms of variable aggressiveness. Sporadic case reports and diverse complex histogenetic source also defy categorization of odontogenic tumors. Many can be diagnosed accurately based on the distinctive clinical, radiological and histopathological presentation. Considerable variations in the clinicopathological presentation of odontogenic tumors can be confusing, increasing the chance of misdiagnosis. An interesting case of adenoid ameloblastoma reported in a 55-year-old male patient in the mandible, presenting with a diverse and intriguing histopathology, is discussed here.

Mixed odontogenic tumour with dentinoid and ghost cells

Ameloblastomas do not generally show evidence of induction, however, rare cases associated with odontome have been reported and are referred to as odontoameloblastomas. We report an unusual case of an ameloblastoma with features of an adenomatoid odontogenic tumour, showing evidence of induction of dentinoid by tumour cells--but without concomitant formation of enamel--and with features of ghost cells. The lesion occurred on the left side of the maxilla in a 31-year-old woman.

Adenoid ameloblastoma with dentinoid

Ameloblastomas seldom cause diagnostic difficulties due to classic histopathological presentations. Adenoid ameloblastoma is a rare variant in this category which can cause problem in diagnosis due to the presence of areas resembling adenomatoid odontogenic tumor (AOT) and occurrence of varying degrees of dentinoid formation. In this article, we report a case of adenoid ameloblastoma with dentinoid, which was diagnosed accurately after the third recurrence. To the best of our knowledge, so far, only 13 cases have been reported of tumors that histologically show features of amelobalstoma and AOT with hard tissue formation. The recurrences were due to under diagnosis of the lesion followed by a conservative treatment.

Adenomatoid odontogenic tumor concomitant with cystic complex odontoma: case report

This case report describes a 10-year-old female patient with an adenomatoid odontogenic tumor developing together with a cystic complex odontoma. This occurrence is considered very unusual. Immunohistochemical detection of cytokeratins AE1/AE3, CK5, CK8, CK10, CK14, CK19 and Ki-67 was performed.

Bilateral adenomatoid odontogenic hamartoma

We report the first case of bilateral odontogenic lesions consistent with several cases of unifocal adenomatoid odontogenic hamartoma in the literature. The lesions were well circumscribed, unilocular, radiolucent, and located in the region of the third mandibular molar region in a 12-year-old female patient. The lesions were composed of odontogenic hard and soft tissues, dental papilla, dentin, enamel matrix, and adenomatoidlike odontogenic epithelium. The lesions were enucleated with no recurrence at 6 months.

International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma

BACKGROUND

Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC).

METHODS

The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines.

RESULTS

CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included.

CONCLUSIONS

Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

Adenomatoid odontogenic tumor (AOT) originating in a unicystic ameloblastoma: a case report

The follicular variant of the adenomatoid odontogenic tumor (AOT) is thought to originate from the reduced enamel epithelium of the dental follicle. The origin of the extra-follicular variant however, remains less clear. This paper presents a case of an extra-follicular AOT, which we believe originated from the epithelial lining of a unicystic ameloblastoma, and reviews the literature. The available evidence seems to indicate that some extra-follicular AOTs might arise as secondary phenomena within pre-existing odontogenic cysts or cystic tumors.

Adenomatoid dentinoma or adenomatoid odontogenic hamartoma: what is the better term to denominate this uncommon odontogenic lesion?

We report two cases of an uncommon odontogenic lesion, previously described as adenomatoid dentinoma. They were well-circumscribed unilocular radiolucent lesions exhibiting discrete radiopacities, located in the left mandibular third molar region. Microscopically they were composed of odontogenic hard and soft tissues, similar to a dental germ. Dental papilla and dentin were easily identified. Odontogenic epithelium formed adenomatoid-like structures, and by scanning electron microscopy a layer of enamel was seen in contact with the dentin. Based on these clinical, radiographic, histological and electron microscopical features we proposed the diagnosis of adenomatoid odontogenic hamartoma. Treatment consisted of surgical removal, and no recurrence was observed. In our opinion all similar cases previously reported pertain to the same spectrum of this lesion and thus should be named as suggested above. Moreover, ultrastructural observations using 5 microm sections can be useful to better characterize the presence of hard tissues.

A case of multiple AOT-like jawbone lesions in a young patient--a new odontogenic entity?

We assessed the immunohistochemical profile of an unusual case of multiple similarly looking tumors in the jawbone of a young patient. Histologically, the tumors exhibited features of adenomatoid odontogenic tumor (AOT) and adenomatoid dentinoma but showed no resemblance to any other defined odontogenic tumor entities. They expressed high amounts of cytokeratin (CK) 8 and 14 together with some Vimentin. A small rim of peripheral cells showed CK 5, 17, and 19 reactivity. Also, these lesions expressed some bcl-2 as well as p53 and Ki67. Histologically and immunohistochemically, the unusual multiple lesions differed in details from a simultaneously examined group of 24 classical AOT cases, suggesting that they may represent a hitherto less well-defined odontogenic tumor entity.

Adenomatoid dentinoma. Report of four cases of an unusual odontogenic lesion

Four cases of a rare odontogenic lesion are reported. In each of the 4 examples, the lesion manifested itself as a well-circumscribed unilocular radiolucency in the mandibular third molar region in an adult. The histopathologic features consisted of an encapsulated proliferation of odontogenic hard and soft tissues. The hard tissue component consisted of dentin deposited in a peripheral ringlike configuration that enclosed odontogenic epithelium resembling adenomatoid odontogenic tumor. Whether this process represents a neoplasm or an odontogenic hamartoma is an unresolved question. Treatment in each case consisted of curettage, and no recurrences were observed.