原文題目(出處)： Peripheral developing odontoma or peripheral ameloblastic fibroodontoma: A rare challenging case. Case Rep Dent 2016; Article ID 9379017
原文作者姓名： Moghadam SA and Mokhtari S
通訊作者學校： Department of Oral and Maxillofacial Pathology, Dental School of Shahid Beheshti University of Medical Sciences, Velenjak Street, Tehran, Iran
報告者姓名(組別)： 潘嬿蓉 Intern I 組
報告日期： 2016/04/13
一. 內文:
Abstract:
Peripheral odontogenic lesions are considered to be rare within the classification of odontogenic tumors. They share the same microscopic characteristics of their central counterparts. Here, we report an ulcerated mass of the maxillary gingiva that on histopathological examination was diagnosed as peripheral developing odontoma or peripheral ameloblastic fibroodontoma. The diagnosis of this tumor is challenging and may lead to unnecessary treatment
二. Case Report
An 8-year-old healthy girl was referred to the pathology department for examination of an isolated and ulcerated soft tissue mass of the palatal gingiva in the region of right canine and deciduous first molar, measuring 0.8 × 0.8 cm with unknown duration
There was no history of trauma to the area. The periapical radiograph did not show any intrabony lesion
Clinical diagnosis：Reactive soft tissue lesion most probably pyogenic granuloma (PG) or peripheral ossifying fibroma (POF)
The cut surface of the lesion was creamy solid.
Histopathologic examination：
−the oral epithelium was totally replaced by fibrinopurulent membrane with bacterial colonization
−The underlying connective tissue demonstrated dental papilla-like structure and irregularly proliferating dental epithelium composed of stellate reticulum-like and tall columnar ameloblast-like cells
−A small accumulation of ghost cells and calcification were also seen.
−The mineralized material was a basophilic deposition without any specific structure and more similar to foci of immature enamel or dentin
−Scattered odontogenic islands resembling the islands of ameloblastic fibroma were seen in dental papilla area
Diagnosed：Peripheral developing complex odontoma Peripheral ameloblastic fibroodontoma
Follow-up：The patient’s post operative course was normal
no evidence of recurrence with 1-year follow-up period 三. Discussion
Odontogenic neoplasms are categorized into ○1peripheral (rare)
○2central
Saghravanian et al.：reported that 4.3% of odontogenic tumors were peripheral.
Several large series：peripheral odontogenic fibroma (most common) Peripheral ameloblastoma (second)
Peripheral odontogenic tumors may be misdiagnosed clinically as common reactive soft tissue lesions in the oral cavity like pyogenic granuloma,irritation fibroma, peripheral giant cell granuloma, and peripheral ossifying fibroma
mixed odontogenic tumors group：○1Odontoma
○2ameloblastic fibroodontoma are composedof odontogenic epithelium and ectomesenchyme
Some authors regard complex odontoma and ameloblastic fibroodontoma as hamartoma rather than true neoplasm
The etiology of odontogenic tumors is indefinite and their source is the remnants of dental lamina that reside in the gingiva (rests of Serres) and develop lingually to those of the primary teeth
al.：the mean age of patients with peripheral developing odontoma was 6.6years which is 10 years younger than the mean age of patients with central odontoma.
This lesion is reported in both boys and girls and does not show sex predilection
Development：
First step is a non-neoplastic type of ameloblastic fibroma (consisting of odontogenic epithelium and odontogenic ectomesenchyme) in which dentin and then enamel are formed
At the end stage, it forms a complex odontoma almost entirely consisting of dental hard tissues
四. Conclusion
Peripheral odontoma and peripheral ameloblastic fibroodontoma are exceedingly rare benign odontogenic lesions thatare treated by conservative excision
The proper diagnosisof these lesions is necessary to avoid confusion with true neoplasms especially odontogenic tumors and prevent extensive surgery Q：以下描述 ameloblastic fibroodontoma，何者錯誤?
A 平均年齡 10 歲，常見在小女孩身上
B 好發位置是下顎後牙區，有時候跟埋伏齒有關連
C Radiographic geatures 為 Well circumscribed unilocular radiolucency，中間有 radiopaque
D 有 capsule 的完整構造。
Answer：A
出處：Oral and Maxillofacial PATHOLOGY
Q：以下描述 Odontoma，何者正確?
A 整體來說，好發於中年族群的下顎。
B 近代部分學者認為他不屬於腫瘤的一種，而是一種 Choristoma。
C 屬於 mixed odontogenic tumor，完全由硬組織所構成。
D 因為完全由硬組織構成，與我們的骨頭構造相近，所以邊緣是 ill-defined
的。
Answer：C
出處：Oral and Maxillofacial PATHOLOGY
