Odontogenic tumors are heterogeneous group of lesions with diverse histopathological and clinical features. Ameloblastic fibro-dentinoma. The ameloblastic fibro-odontoma (AFO) is a rare mixed odontogenic tumor. .. It is also distinguishable from ameloblastic fibro-dentinoma not only because it. Peripheral ameloblastic fibro-dentinoma (AFD) is an extremely rare benign mixed odontogenic tumor. From a review of the English-language literature, to the.

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This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Ameloblastic fibro-odontoma AFO predominantly occurs in the jaw bones of children and young adults.

Extraosseous AFO is extremely rare. We describe a peripheral ameloblastic fibro-odontoma in the maxillary gingiva of a 3-year-old girl. The clinical appearance resembled fiery red reactive gingival lesions. The histopathological examination of the excised lesion showed small islands and cords of odontogenic epithelium with cellular myxoid stroma in the subepithelial tissue.

The mass contained calcified material and an enamel-like deposit. Many small blood vessels appeared in the connective tissue surrounding the odontogenic epithelium. There was no recurrence after the 1-year follow-up. Because this lesion clinically resembles other nonneoplastic lesions and is very rare in gingiva, establishing a correct diagnosis is achieved only based on specific histological characteristics.

Conservative excision of the tumor is the treatment of choice. The soft tissue constituent of the tumor is composed of epithelial cords and small isles of odontogenic epithelium associated with a primitive-appearing myxoid connective tissue that appears like the dental papilla.

The hard tissue constituent consists of foci of dentin and enamel with varying degrees of mineralization [ 2 ]. It is usually slow developing and is usually seen in young persons with a mean age between 8 and 12 years [ 13 ]. A majority of AFO is intraosseous and is associated with unerupted teeth. Peripheral extraosseous, soft tissue AF or AFO arising in gingival tissue is even rarer than their intraosseous counterparts [ 4 — 6 ]. Although molecular alternations are reported in different types of odontogenic tumors, their pathogenesis remains to be elucidated [ 78 ].

A three-year-seven-month-old girl was referred to the Pediatric Dentistry Section, Department of Stomatology, National Cheng Kung University Hospital, to have a swelling and erythematous mass on the facial gingiva of the primary maxillary right central incisor evaluated.

Immediately after the eruption, it was positioned more palatally than the adjacent incisors. A small, white, tooth-like substance existed on the facial gingiva of this tooth. Then the tooth-like substance spontaneously exfoliated. She could not remember that her daughter had undergone any trauma. They went to a local dental clinic for evaluation. The dentist performed endodontic treatment for the central incisor because he found caries and speculated that the gingival swelling had an endodontic origin.


Five months later, they went to the same clinic because the lesion became larger. The dentist decided to refer the child to our hospital. During her initial examination in our hospital, we noticed a fiery red gingival mass that neither bled nor felt palpation pain Figure 1 a.

The probing depths of the tooth were within normal range. The tooth was a little palatally displaced but not mobile Figure 1 b. The periapical radiograph revealed no periapical lesion, root resorption, or radiopaque abnormality Figure 1 c. Our initial but tentative diagnosis was a pyogenic granuloma. After the lesion had been locally debrided and irrigated with 0. After we had consulted with periodontics and oral-maxillofacial surgery specialists, we suggested an excisional biopsy under general anesthesia for the patient.

After we had obtained the consent of the parents, we removed the mass using surgical scalpels; bleeding was stopped using electrocautery in the operating room. Amoxicillin and acetaminophen were prescribed for the patient. A microscopic examination revealed a small island and cords of odontogenic epithelium in a loose and primitive-appearing connective tissue that resembled dental papilla. Abundant small blood vessels surrounded the odontogenic epithelium Figure 2.

The pathological diagnosis was an ameloblastic fibro-odontoma. A one-year postoperative follow-up revealed no evidence of recurrence, but only a mild gingival inflammation Figure 3.

Ameloblastic fibro-odontoma

Isotype immunoglobulins Abcam were used to replace primary antibodies as negative control. The slides were counterstained with Mayer hematoxylin and photographed using an optical microscope BX61; Olympus, Tokyo, Japan equipped with an imaging system Stream; Olympus.

The IHC results showed that amelogenin was strongly expressed in enamel epithelium. The calcified matrix in the tissue sections was also positive for amelogenin staining. Some of the stromal cells, leukocytes, and endothelial cells were also positive for CD44 staining. CD31 staining confirmed that there were abundant small blood vessels in the tumor stroma, especially in the area adjacent to the enamel epithelium Figure 4. Some pathologists consider them as separate entities.

Others regard them as sequential stages beginning from AF at one extreme and complex odontoma at the other extreme with AFD and AFO in the intermediate stages. AFD is defined as a neoplasm similar to AF that concurrently shows formation of dentin or dentinoid [ 20 ]. The peripheral types of mixed odontogenic tumors are much rarer than their intraosseous counterparts [ 1 — 6 ]. The age range is 2. More female cases are reported than male ones. The reported extraosseous tumors do not appear in the oral mucosa other than gingiva.

Compared to their intraosseous counterparts, peripheral tumors tibro more located in maxillary amelblastic anterior to first molars. Their clinical ameloblastiv resemble much those of localized reactive gingival lesions [ 4 — 6 ]. Localized reactive hyperplastic lesions in gingiva can be classified into 4 subcategories: Two additional pathologies, peripheral ameloblastoma and calcifying epithelial odontogenic tumor, should also be distinguished [ 4 ].

The definitive differentiations between these clinically similar diseases depend on their microscopic findings. Our clinical diagnosis for this case was pyogenic granuloma because of its erythematous appearance. In our patient, numerous small blood vessels were distributed near the odontogenic epithelium in the tissue sections. There may be two reasons for the high vascularization of this lesion.


First, a gingival lesion is subject more than its intraosseous counterpart to constant irritation dentlnoma plaque, calculus, food impaction, and low-grade trauma. Second, there are several indications that amelogenin protein, highly expressed in the odontogenic epithelium of this lesion, is actually a proangiogenic molecule [ 23 ]. CD44, a hyaluronic acid receptor, is one of fentinoma most commonly studied surface markers, which is expressed by almost every tumor cell [ 24 ]. Studies have reported that CD44 is highly expressed in ameloblastomas [ 13 ].

Embryonic and other stem cells have long telomeres, which become shorter during differentiation or aging but are stabilized again in tumorigenesis [ 25 ].

Ameloblastic fibro-odontoma

Based on the figro literature, amelogenin secreted by the odontogenic epithelium may contribute to the red appearance of the lesion. The standard treatment for intraosseous AF and AFO is conservative surgery with enucleation and a close clinical follow-up [ 3 ]. The recurrence rate of intraosseous AFO is uncommon: Because peripheral AFO is so rare, there is no published study that estimates its recurrence rate after surgical excision.

Most studies suggest that conservative excision of the tumor with minimal but adequate margins is the treatment of choice [ 4qmeloblastic ]. We report a rare case of gingival AFO with the classic microscopic features of its intraosseous counterpart. Because peripheral AFOs clinically resemble other neoplastic and nonneoplastic lesions in the gingiva, establishing a correct diagnosis is difficult and is possible only based denntinoma a histological distinction.

It is plausible that amelogenin expressed by the enamel epithelium contributes to the fiery red phenotype. It appears that the peripheral AFO should be initially treated by conservative surgical therapy and the patient should be clinically aameloblastic up for recurrence. Case Reports in Dentistry. Indexed in Web of Science.

Subscribe to Table of Contents Alerts. Table of Contents Alerts. Abstract Ameloblastic fibro-odontoma AFO predominantly occurs in the jaw bones of children and young adults. Case Presentation A three-year-seven-month-old girl was referred to the Pediatric Dentistry Section, Department of Stomatology, National Cheng Kung University Hospital, to have a dentimoma and erythematous mass on the facial gingiva of the primary maxillary right central incisor evaluated.

Clinical and radiographic appearances. There was no observable radiopaque abnormality in the periapical radiograph. Hematoxylin and eosin staining for the gingival lesion. One of them clearly exhibits enamel organ differentiation.

Clinical appearance 1 year after excisional biopsy for the gingival lesion. CD31 staining appeared in the endothelial cells of the tumor stroma, especially in the area adjacent to the enamel epithelium. View at Google Scholar G. View at Google Scholar A. View at Google Scholar J.