Scholarly article on topic 'Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature'

Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature Academic research paper on "Clinical medicine"

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{"Mixed odontogenic tumor" / "Ameloblastic fibro-odontoma" / "Immature odontoma" / Hamartoma}

Abstract of research paper on Clinical medicine, author of scientific article — Marcello Augello, Alessandro Rabufetti, Georges Ghazal, Hueseyin Yurtsever, Christoph Leiggener

Abstract The ameloblastic fibro-odontoma (AFO) is a rare mixed odontogenic tumor. Clinically AFO presents as a hamartoma or immature odontoma. The AFO is a well-encapsulated, painless, slow-growing and expanding tumor in young patients. Histologically, it has been classified as an ameloblastic fibroma or odontoma. Despite numerous efforts, there is still considerable confusion concerning the nature, the histology and the surgical therapy of this lesion. However, it can present with progressive growth causing bone destruction and significant deformity. The transformation of AFO in sarcoma is also known and extremely rare. Therefore a long term follow up is recommended. Enucleation still remains the gold standard. We are discussing our experience with AFO focused on children in clinical and surgical features and reviewing the relevant literature.

Academic research paper on topic "Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature"

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Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature

Marcello Augello, Alessandro Rabufetti, Georges Ghazal, Hueseyin Yurtsever, Christoph Leiggener

PII: S2214-5419(17)30001-9

DOI: 10.1016/j.omsc.2017.01.001

Reference: OMSC 24

To appear in: Oral and Maxillofacial Surgery Cases

Received Date: 19 November 2015 Revised Date: 19 October 2016 Accepted Date: 21 January 2017

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Editor in Chief Dr. Janice S. Lee

Please cite this article as: Augello M, Rabufetti A, Ghazal G, Yurtsever H, Leiggener C, Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature, Oral and Maxillofacial Surgery Cases (2017), doi: 10.1016/j.omsc.2017.01.001.

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Ameloblastic fibro-odontoma in children. Clinical aspects and review of the literature.

A O O A A

Marcello Augello'3, Alessandro Rabufetti2, Georges Ghazal1, Hueseyin Yurtsever4, Christoph Leiggener1,2

'Department of Oral and Cranio-Maxillofacial Surgery, Kantonsspital Aarau, Switzerland

2Department of Oral and Cranio-Maxillofacial Surgery, University Hospital Basel, Switzerland

3Hightech Research Center of Cranio-Maxillofacial Surgery, Allschwil, Switzerland 4Department of Pathology, Kantonsspital Aarau, Switzerland

Corresponding author:

Dr. Dr. Marcello Augello Tellstrasse CH-5001 Aarau

+41 62 8386309

marcello.augello@ksa.ch

Declaration of interest: The authors report no conflicts of interest.

Summary

The ameloblastic fibro-odontoma (AFO) is a rare mixed odontogenic tumor. Clinically AFO presents as a hamartoma or immature odontoma. The AFO is a well-encapsulated, painless, slow-growing and expanding tumor in young patients. Histologically, it has been classified as an ameloblastic fibroma or odontoma. Despite numerous efforts, there is still considerable confusion concerning the nature, the histology and the surgical therapy of this lesion. However, it can present with progressive growth causing bone destruction and significant deformity. The transformation of AFO in sarcoma is also known and extremely rare. Therefore a long term follow up is recommended. Enucleation still remains the gold standard. We are discussing our experience with AFO focused on children in clinical and surgical features and reviewing the relevant literature.

Keywords:

Mixed odontogenic tumor, ameloblastic fibro-odontoma, immature odontoma, hamartoma

Introduction

Ameloblastic fibro-odontoma (AFO) belongs to the family of mixed odontogenic tumors. The term AFO was first used by Hooker [1] and had originally been termed ameloblastic odontoma. It can be defined as a neoplasm composed of proliferating odontogenic epithelium embedded in a cellular ectomesenchymal tissue that resembles dental papilla with varying degree at inductive change and dental hard tissue formation. In 1971 the WHO suggested that this term was inappropriate since it encompasses two types of odontogenic tumors that share a different histology and biologic behavior [2]. Despite numerous efforts, however, there was still considerable confusion concerning the nature and relationship between mixed odontogenic tumors and related lesions. According to the revised WHO classification, it is a benign tumor without invasive growth, contrastingly to ameloblastoma [3]. Nevertheless a potential for malignant transformation of AFO to ameloblastic fibrosarcoma has been shown [4]. The disease is rare and occurs with equal frequency in the maxilla and mandible, with no gender preference [5]. The mean age of incidence is from 8 to 12 years. Due to this fact we report focused on children. According to the literature, AFO is not an aggressive tumor and it can be treated adequately with curettage when managing small lesions [6,7,8]. However, there is no really consensus about the treatment of extensive tumors. The purpose of the present paper was to discuss and to analyze the clinical, radiological and treatment features of this disease based on two cases of huge AFOs in order to update and improve our knowledge and diagnostic ability of this entity.

Case 1

An 11-years-old boy was referred to the department of maxillofacial surgery at the Hospital Aarau, Switzerland, to evaluate an indolent swelling of the right posterior mandible of 4 months duration. The medical, social and family histories were unremarkable, as were the results of a review of systems and physical examination. The extraoral examination revealed a slight facial asymmetry with an asymptomatic swelling on the right side of the mandible without signs of inflammation. Oral inspection showed a bony hard bulge in the right mouth vestibule extending from from the lower right first molar to the wisdom tooth region. The border of the lesion

was well circumscribed. The lower right first molar) was in occlusion. There was a normal sensibility of the lower lip. There was no history of local trauma or infection. A good oral hygiene was applied. The initial panoramic radiography revealed a well-defined radiolucent region, which contained an irregular radiopaque mass of 35x25mm of diameter in contact with the displaced wisdom tooth and the second molar. This lesion occupied a zone from the lower right first molar area to the right ramus (figure 1). Cone beam computer tomography showed an expansive well-circumscribed lesion containing at the interior a calcified mass compatible with odontogenic tissue (figures 2a-b). Considering the clinical and radiographic examinations, our presumptive diagnosis was complex odontoma. As the clinical and radiological presentations alone could not show a definitive diagnosis, incisional biopsy was performed. Specimen was sent to the department of pathology. The tissue was suspicious for an odontogenic tumor. The patient underwent under general anesthesia by a transoral surgical approach the enucleation of the lesion and careful curettage of the surgical cavity in order not to fracture the basal bone and not to damage the inferior alveolar nerve. Because the wisdom tooth and the second molar were directly involved with the lesion, we decided to extract these teeth. Afterwards the cavity was filled with cancellous bone from the right iliac crest. The microscopic evaluation of the specimen showed a mixed epithelial-mesenchymal odontogenic neoplasm (figures 3a-b). The epithelial component was consisted of cells, mostly in trabecular arrangement, with cytologic imitation of the stratum reticulare of the dental enamel organ. The mesenchymal component was composed of spindle cells and resembled the connective tissue of the dental papilla. Neither atypia nor mitotic figures were seen. Furthermore, irregular islands of dental hard tissue were present in the stroma, identifiable as dysplastic dentin or dental enamel. The microscopic findings all together were indicative for an ameloblastic fibro-odontoma. Based on these characteristics the diagnosis was AFO. The postoperative course was uneventful. The sensibility of the mentalis nerve was not affected. The patient is being followed up postoperatively for 31 months and there is no sign of recurrence (figure 4). There was no history of local trauma or infection.

Case 2

A 12-year-old boy was referred to us because of a teeth eruption disturbance in the right posterior maxilla and a progredient swelling. The medical, social and family histories were unremarkable. The extraoral examination revealed only a very slight asymptomatic swelling on the right posterior side of the maxilla. There were no signs of inflammation. The intraoral examination showed hyperplasia of the vestibule and the maxillary bone of the right side. There was a cranially displacement of the upper right first molar and the last molar of the first dentition. The initial panoramic and lateral radiography revealed a well-defined irregular radiopaque mass with a radiolucent border in projection of the maxillary sinus which was in contact with the displaced teeth (figure 5). For further investigation a cone beam computer tomography was performed. It showed an expansive well-circumscribed area of radiolucent and radiopaque mass towards the body of the zygomatic bone and a constriction of the maxillary sinus (figures 6a-b). Considering the clinical and radiological pictures the possible differential diagnosis was calcifying epithelial odontogenic tumor, adenomatoid odontogenic tumor and ameloblastic fibro-odontoma. Also in this case an excision of the tumor and a histologically verification of the tissue was indicated. This revealed the presence of ameloblastic fibro-odontoma tissue. Under general anesthesia with endotracheal intubation as the previous case the enucleation of the lesion with carefully curettage and extraction of the cranially displaced teeth, i.e. the second milk tooth and the first permanent molar, was done by a transoral surgical approach. No bone augmentation was needed. There was no penetration into the maxillary sinus. It followed the wound closure by a trapezoidal flap. On microscopic analysis the specimen showed, similar to the first case, a mixed epithelial-mesenchymal odontogenic neoplasm (figures 7a-b). Embedded in a mesenchymal component with similarity to the connective tissue of the dental papilla there were groups of epithelial cells with resemblance to the stratum reticulare of the dental enamel organ. Focally, formation of dental hard tissue substance was to be found. There was no evidence of malignancy. As in the first case the diagnosis of an ameloblastic fibro-odontoma was made. Based on clinicopathological correlation the final diagnosis of AFO was given. The postoperative course was uneventful. 29 months after surgery there was no signs of

recurrence and the clinical and radiological appearances of the bone and surrounding soft tissue were normal (figure 8).

Discussion

A systematic, multilingual review of medical literature from 1900 until today was conducted, using Pubmed, OVID, MEDLINE, Cochrane Database of Systemic Reviews, PUBFACTS scientific publication data. The search was performed with the key word "ameloblastic fibro-odontoma". The term ameloblastic fibro-odontoma (AFO) appears in the World Health Organization (WHO) classification of mixed odontogenic tumors, which includes ameloblastic fibroma, AFO, odontoma and odonto-ameloblastoma. These lesions are defined as neoplasms composed of proliferating odontogenic epithelium embedded in cellular ectomesenchymal tissue that resembles dental papilla, with varying degrees of inductive changes and dental hard tissue formation without invasive growth [9]. Previously it has been a matter of dispute whether the mixed odontogenic tumors (AFO, ameloblastic fibroma and odontoma) should be classified as separate entities or if they merely represent various stages of the same lesion, and it will mature over time resulting ultimately in the formation of an odontoma and represent different stages of development of a single entity [10]. The last hypothesis has been questioned by other authors [11,12]. They could demonstrate that in the case of further recurrences of the latter entity showed the same appearance as the original tumor. In addition, the possible sarcomatous transformation of each of these entities (with the exception of odontoma) gives a neoplastic importance and independence. In this sense an attempt to explain the pathophysiology Praveen [13] proved in a test model of immune staining with anti-amelogenin sera that tumor epithelium and mesenchyme can potentially mimic the full spectrum of phenotypic changes, and the cellular and molecular events that regulate normal odontogenesis most likely operate to a certain extent in the pathogenesis and differentiation of odontogenic tumors. Others immunohistological analysis pathways showed that odontogenic epithelium expresses high levels of CD44 and p-catenin. CD44, a hyaluronic acid receptor, is one of the most commonly studied surface markers, which is expressed by almost every tumor cell [14]. Studies have reported that CD44 is highly expressed in

ameloblastoma [15]. p-catenin is an important regulator for telomere length. Embryonic and stem cells have long telomeres which become shorter during differentiation or aging [16]. A genetic engineering study showed that mouse tooth expressing p-catenin in oral epithelium give rise to odontoma-like structures containing dozens of malformed teeth [17]. Clinically, it has been revealed that p-catenin is highly expressed in odontogenic tumors [18,19]. Based on the existing literature, the immunohistochemistry staining implied that CD44 and p-catenin might be expressed in AFO lesions. Nevertheless further studies are needed for this purpose. Most now agree that ameloblastic fibro-odontoma exists as a distinct entity, but it can be histologically indistinguishable from immature complex odontoma. In our study no immunohistological analysis was performed.

In a recent study, AFO has been reported with a prevalence range of 1-3.4% within odontogenic tumors among different regions [20]. There is no gender predilection, with the lesion being equally found in the mandible and maxilla, normally in the molar region [20,21]. Although in the study of Buchner [22] reviewing published cases series of totally 114 patients it was shown that the mandible-to-maxilla ratio was 1.85:1 and nearly 80% of the lesions were located in the posterior region of the jaws. Generally it is seen in the first and second decades of life, which might also be a characteristic of the lesion [23] with mean age of 11.5 years (range 6 months to 39 years). However, AFO may also occur at advanced ages [24,25]. Previously Philipsen [21] declared that the mean age of AFO cases falls when compared with ameloblastic fibroma and ameloblastic fibro-dentinoma, supporting the suggestion that age is a critical feature in AFO diagnosis and is thus an important characteristic in the differential diagnosis.

The most presenting complaints of AFO are asymptomatic swelling, delayed tooth eruption in the affected region and a well-defined mixed radiological appearance that is similar to other odontogenic neoplastic formations, such as immature complex odontoma, calcifying epithelial odontogenic tumor and adenomatoid odontogenic tumor. The calcifying epithelial odontogenic tumor (Pindborg tumor) has a definite predilection for the mandible and mostly develops in the premolar-molar area, with 52% association with unerupted or impacted teeth. The adenomatoid odontogenic tumor is fairly uncommon, but it is seen more in young people. Two thirds of the cases are found in females. Two thirds of cases are located in the anterior maxilla, and one third is present in the anterior mandible [26]. Nevertheless, final diagnosis is

made according to microscopic evaluation demonstrating islands of odontogenic epithelium embedded in cell-rich ectomesenchyme similar to dental papilla. AFO can be differentiated from ameloblastic fibroma by the radiological appearance as well as through histological evaluation. It is also distinguishable from ameloblastic fibro-dentinoma not only because it shows dental structures resembling dentine but also because it contains enamel-like tissues. Thus the formation of AFO might be based on enamel matrix production which is one of the most important features of the lesion.

The radiographic findings of these lesions usually show a mixed mass of a well-defined radiolucent portion containing various amounts of radiopaque material of irregular size and form. The ratio of radiopaque to radiolucent areas differs from one lesion to another. Sometimes the mineralized element in the tumor predominates, and the lesion may resemble an odontoma. For the exact localization of the tumor and to make surgical treatment decisions to preserve the adjacent vital structures a CT scan or a conebeam CT scan is recommended.

The treatment of AFO is associated with a conservative surgical approach. Enucleation still remains the gold standard due to a non-invasive growth of the disease. This measure shows good results with a good prognosis. The enucleation will allow maintenance of adequate periosteum and bone for spontaneous regeneration in defects of young patients. In our first case after a transorally curettage of the lesion, due to its extension with a potentially higher risk for fracture of the mandible we decided to reconstruct the defect with iliac crest cancellous bone. In the second case we left the cavity of the upper right jaw to spontaneous bone regeneration. Only in cases of larger lesions a more extensive surgery is needed and then a transcervical surgical approach should be considered. Determination of a case-dependent treatment plan may provide an optimum outcome. Preservation of the unerupted tooth or its removal depends on the clinical situation. We suggest to maintain the involved tooth/teeth if there is not an interfering with the enucleation of the tumor, and to allow a spontaneous eruption. Recurrences are rare and have been attributed to the inadequate surgical removal at the time of initial treatment. If there is a recurrence accompanied by change of the histological pattern towards a more unorganized fibrous stroma, with displacement of the epithelial component, then more extensive treatment procedures appear to be indicated [27]. Our two cases showed extended lesions which needed a large curettage and the

extraction of the unerupted teeth. In our first case a bone grafting was performed due to a large cavity and higher risk for a fracture of the lower jaw. For AFO the possibility for a malignant transformation to a ameloblastic fibrosarcoma has been proved [28,29]. Malignant changes can occur after 10 - 12 years. In that case a complete surgical excision is the treatment of choice. A recent study showed the efficacy of chemotherapy responsiveness in a patient with multiply relapsed ameloblastic fibro-odontosarcoma of the maxilla [30]. Because of possibility of a malignant transformation of AFO we advocate following up the patients for a long term.

Conclusion

Clinicians should keep in mind that a radiopaque mass in the posterior maxilla or mandible of young patients associated with unerupted teeth can be a possibility of rare mixed odontogenic tumor like AFO. Like most authors we recommend tumor enucleation as the first step in treatment. Only in the case of repeated recurrences or evident malignancy we recommend performing a more extensive treatment. Although AFO is a rare benign neoplasm a low incidence of malignant transformation is given. A long term follow up over many years is advised.

References

1. Hooker SP. Ameloblastic odontoma: Analysis of twenty six cases. Oral Surg 24: 375, 1967.

2. Pindborg JJ, Kramer IR, Torloni H. In: Histological Typing of Odontogenic Tumours, Jaw Cysts, and Allied Lesions. International Histological Classification of Tumours. Book 5. Geneva, Switzerland: World Health Organization; Springer-Verlag Berlin Heidelberg, GmbH, 18, 1971

3. Barnes L, Eveson JW, Reihcart P: Pathology & genetics of head and neck tumours- World Health organization classification of tumours.v.9. IARC press. 2005.

4. Howell RM, Burkes EJ: Malignant transformation of ameloblastic fibro-odontoma to ameloblastic fibrosarcoma. Oral Surg 43:391 401, 1977.

5. Shafer WG, Hine MK, Levy BM: A textbook of oral pathology, Philadelphia, PA: W.B. Saunders, 304e 313, 1983.

6. De Riu G, Meloni SM, Contini M, Tullio A: Ameloblastic fibro-odontoma. Case report and review of the literature. J Craniomaxillofac Surg 38: 141e 144, 2010.

7. Pontes FSC, Pontes HAR, Nogueira JES, Cury SEV, Araujo JF, Fonseca FP, Pinto Jr DS: Ameloblastic fibro-odontoma: case report with maintenance of the involved teeth. Int J Pediatr Otorhinolaryngol Extra 3: 48e 52, 2008.

8. Zouhary KJ, Said-Al-Naief N, Waite PD: Ameloblastic fibro-odontoma: expansile mixed radiolucent lesion in the posterior maxilla: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 106: 15e 21, 2008.

9. Takeda Y, Tomich CE: WHO international histological classification of tumours. Vol 9 IARC Press, 309, 2005.

10. Cahn LR, Blum T. Ameloblastic odontoma: case report critically analyzed. J Oral Surg 10: 169 170, 1952.

11. Regezi JA, Kerr DA, Courtney RM: Odontogenic tumors: analysis of 706 cases. J Oral Surg 36: 771 778, 1978.

12. Slootweg P.J.: An analysis of the interrelationship of the mixed odontogenic tumors -ameloblastic fibroma, ameloblastic fibro-odontoma, and the odontomas. Oral Surg Oral Med Oral Pathol 51: 266 276, 1989.

13. Praveen A, Venkatesh V, Krishnanand S, Nagaraja A, Komali Y: Amelogenin in odontogenic cysts and tumors: An immunohistochemical study. Natl J Maxillofac Surg 5: 172 179, 2014.

14. Keysar SB, Jimeno A: More than markers: biological significance of cancer stem cell-defining molecules, Molecular Cancer Therapeutics 9: 2450 2457, 2010.

15. Sathi GA, Tamamura R, Tsujigiwa H: Analysis of immunoexpression of common cancer stem cell markers in ameloblastom. Experimental and Therapeutic Medicine 3: 397 402, 2012.

16. Hoffmeyer K, Raggioli A. Rudloff A: Wnt/p-catenin signaling regulates telomerase in stem cells and cancer cells. Science 336: 1549 1554, 2012.

17. Jarvinen E, Salazar-Ciudad I, Birchmeier W, Taketo MM, Jernvall J, Thesleff I: Continuous tooth generation in mouse is induced by activated epithelial Wnt/p-catenin signaling. Proceedings of the National Academy of Sciences of the United States of America, 103: 18627 19632, 2006.

18. Miyake T, Tanaka Y, Kato K: Gene mutation analysis and immunohistochemical study of beta-catenin in odontogenic tumors. Pathol Int 56: 732 737, 2006.

19. Tanaka A, Okamoto D, Yoshizawa D: Presence of ghost cells and the Wnt signaling pahtway in odontomas. J Oral Pathol Med 36: 400 404, 2007.

20. Buchner A, Merrell PW, Carpenter WM. Relative frequency of central odontogenic tumors: a study of 1,088 cases from Northern California and comparison to studies from other parts of the world. J Oral Maxillofac Surg 64: 1343 1352, 2006.

21. Philipsen HP, Reichart PA, Praetorius F. Mixed odontogenic tumours andodontomas. Considerations on interrelationship. Review of the literature and presentation of 134 new cases of odontomas. Oral Oncol 33: 86 99, 1997

22. Buchner A, Kaffe I, Vered M: Clinical and Radiological Profile of Ameloblastic Fibro-Odontoma: an Update on an Uncommon Odontogenic Tumor Based on a Critical Analysis of 114 Cases. Head and Neck Pathol 7: 54 63, 2013.

23. Takeda Y: Ameloblastic fibroma and related lesions: current pathologic concept. Oral Oncol 35: 535 540, 1999.

24. Chang H, Precious DS, Shimizu MS. Ameloblastic fibro-odontoma: a case report. J Can Dent Assoc 68: 243 246, 2002.

25. Yagishita H, Taya Y, Kanri Y, Matsuo A, Nonaka H, Fujita H, et al. The secretionof amelogenins is associated with the induction of enamel and dentinoid in anameloblastic fibro-odontoma. J Oral Pathol Med 30: 499 503, 2001.

26. Nonaka CF, de Souza LB, Quindere LB (2007). Adenomatoid odontogenic tumour associated with dentigerous cyst--unusual case report. Rev Bras Otorinolaringol 73: 129 131, 2001.

27. Friedrich RE, Segert J, Donath Ket:. Recurrent ameloblastic fibro-odontoma in a 10-year old boy. J Oral Maxillofac Surg 59: 1362 1366, 2001.

28. Herzog U, Putzke HP, Bienengraber V, Radke C: The ameloblastic fibro-odontoma e an odontogenic mixed tumor progressing into an odontogenic sarcoma. Dtsch Z Mund Kiefer Gesichtschir 15: 90e 93, 1991.

29. Howell RM, Burkes EJ: Malignant transformation of ameloblastic fibro-odontoma to ameloblastic fibrosarcoma. Oral Surg Oral Med Oral Pathol 43: 391e 401, 1977.

30. Gatz SA, Thway K, Mandeville H, Kerawala C, MAcVicar D, Chisholm J: Chemotherapy responsiveness in a patient with multiply relapsed ameloblastic fibro-odontosarcoma of the maxilla. Pediatr Blood Cancer 62: 2029-2032, 2015.

Captions Figure 1

The orthopantomogram shows a radiopaque mass with radiolucency in the periphery in a zone from the first molar to the right ramus. Inside are located the two unerupted and displaced teeth.

Figure 2a, 2b

Cone Beam CT-axial and coronar sections revealing expanded cortices with a hyperdense area surrounded by hypodense rim (suggestive of fibrous-capsule) in the angular region of the mandible inferior to which is the impacted tooth

Figure 3a, 3b

Medium-power views of the tumor with epithelial and mesenchymal components (3a) and formation of dental hard tissue substance (3b). There are no signs of malignancy.

Figure 4

31 months after surgery there are no signs of recurrence in the orthopantomogram. Figure 5

A radiopaque mass in projection to the maxillary sinus on the right site with unerupted teeth is shown it this orthopantomogram.

Figure 6a, 6b

Axial and coronal slices of a CBCT scan: These slices show the calcified mass with displacement as well the molar of the permanent dentition as the last milk molar posteriorly and cranially.

Figure 7a, 7b

High-power views of the mixed tumor with epithelial and mesenchymal areas (7a) as well as dental hard tissue substance (7b). There is no evidence of malignancy.

Figure 8

X-ray 29 months postoperative without signs of recurrence.

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Highlights

Clinicians should keep in mind that a radiopaque mass in the posterior maxilla or mandible of young patients associated with unerupted teeth can be a possibility of rare mixed odontogenic tumor like AFO. Like most authors we recommend tumor enucleation as the first step in treatment. Only in the case of repeated recurrences or evident malignancy we recommend performing a more extensive treatment. Although AFO is a rare benign neoplasm a low incidence of malignant transformation is given. A long term follow up over many years is advised. With this article we want to make the reader aware of this disease the treatment option and also in view of a possible malignant transformation over the years. We also discuss the immunohistochemical analysis as a new and alternative diagnostic tool.

Proof of consent

We hereby confirm that the parents of the children, which are listed in the case reports, have been informed about the publication of x-rays and that they agree.