Primordial odontogenic tumor (POT) has been reported only as an intraosseous lesion. Here, we describe the case of POT originating from the maxillary gingiva of a 3-year-old male infant. The patient was referred to our hospital with the chief complaint of a tumor of the right maxillary gingiva. On examination, a pedunculated tumor measuring 7 × 7 mm was observed on the right maxillary gingiva. Dental X-ray showed a lesion that exhibited mixed radiolucency with radiopacity in the maxilla next to the impacted second primary molar. The lesion was excised under general anesthesia. Histopathological examination of the lesion showed proliferation of dental papilla-like connective tissue and columnar ameloblast-like epithelium cells. Thus, we finally diagnosed the lesion as POT. The postoperative course was uneventful and there was no evidence of recurrence of the lesion 3 years after the operation.
POT is defined as a novel benign mixed epithelial and mesenchymal odontogenic tumor in the latest WHO Classification of Head and Neck Tumors.
Although 17 cases of POT has been reported, they has been described only as an intraosseous lesion.
This is the first report of peripheral type of POT which is defined as a novel benign odontogenic tumor in the latest WHO Classification.
POT should be differentiated from the peripheral type of ameloblastic fibroma, developing odontoma, and odontogenic myxoma.
The analysis of the total tumor and careful interpretation of histopathological findings are crucial for the correct diagnosis of POT.
Primordial odontogenic tumor (POT) was classified into benign mixed epithelial and mesenchymal odontogenic tumor in the 4th edition of the World Health Organization (WHO) Classification of Head and Neck Tumors in 2017 1 , and it was first reported by Mosqueda-Taylor et al. [ ] in 2014. POT clinically appears as a well-defined radiolucent intraosseous tumor involving adjacent unerupted teeth in early age. Microscopically, POT is composed of variably cellular to loose fibrous tissue with areas similar to dental papilla, entirely surrounded by cuboidal to columnar epithelium resembling the inner enamel epithelium of the enamel organ [ , ]. To date, there have been only 17 reported cases of POT cases, all of which involved intraosseous lesions [ ].
Here, we report a case of peripheral POT that occurred in the right maxillary gingiva of a 3-year-old male infant.
The patient was a 3-year-old male infant who presented with a painless mass in the right upper gingiva. His parents had noticed the mass 2 weeks before this visit. His family and medical histories were unremarkable. Intra oral examination showed an exophytic mass on the gingiva with missing the upper right second primary molar. The mass measured approximately 7 × 7 mm with a mixture of red and white appearance centrally overlying the pseudomembrane ( Fig. 1 ). The lesion could be felt as an elastic, hard and pedunculated mass. Dental X-ray showed a radiolucent lesion in the maxillary gingiva next to the impacted second primary molar ( Fig. 2 ). An excisional biopsy was performed under general anesthesia. Histopathological examination showed a pedunculated lesion with proliferation of dental papilla-like connective tissue ( Fig. 3 A) and columnar ameloblast-like epithelium cells in the invaginated epithelium ( Fig. 3 B). Thus, we finally diagnosed the lesion as POT. The postoperative course was uneventful and there was no evidence of recurrence of the lesion 3 years after the operation.