Primordial Odontogenic Tumour: A Systematic Review ^†

1. Introduction

Primordial odontogenic tumor (POT) is a novel entity that was described in 2014 and that is included in the group of benign mixed epithelial and mesenchymal odontogenic tumors [1].

In recent years, several papers have added new cases with some clinical and histopathological aspects that slightly differ from those described in the original report, or that had not been previously observed.

The aim of this systematic review is to update all available data on POT published in the literature and to identify those features of the neoplasm that require further investigation.

2. Materials and Methods

A systematic review of literature was conducted using PubMed, Embase, Web of Science and Scopus and following PRISMA guidelines [2]. J-Stage, LILACS and Google Scholar were also checked. Publications reporting cases with enough clinicopathological information were included, without any time or language restrictions. Histopathological, immunohistochemical or radiological studies were considered for qualitative analysis.

3. Results

A total of 28 publications were included (Figure 1). Sixteen papers were used for quantitative analysis (Figure 2;

Table 1. Epidemiological, clinical, radiographic, macroscopic and therapeutic features of published POT cases.

			EPIDEMIOLOGICAL DATA			CLINICAL FEATURES			RADIOLOGICAL ASPECTS					MACROSCOPIC APPEARANCE				THERAPY AND FOLLOW-UP
CASE n°	Year	Author	AGE	SEX	REGION	PAIN	CLINICAL APPEARANCE	TIME BEFORE DIAGNOSIS	SITE	RX APPEARANCE	TOOTH INVOLVEMENT	ROOT RESORPTION	RX DIAMETERS	MACROSCOPIC DIMENSIONS	LOBULES	CYSTIC SPACES	TOOTH/NEOPLASM	DIFFERENTIAL DIAGNOSIS	SURGICAL APPROACH	RECURRENCE	FOLLOW-UP
1	2014	Mosqueda-Taylor A et al.	18	M	Latin America/Hispanic†	Asymptomatic	Buccal swelling	6 months	Left posterior mandible; angle	RL, UL, well defined	enclosing the crown of the third molar	YES (second molar)	45 X 40 mm	N/A	multilobated	NO	embedded	Dentigerous cyst, ameloblastoma	Enucleation with third molar	NO	20 years
2	2014	Mosqueda-Taylor A et al.	16	M	Latin America/Hispanic†	Asymptomatic	Buccal and inferior mandibular cortical bone expansion	4 months	Left posterior mandible; angle	RL, UL, well defined	enclosing the crown of the third molar	N/A	55 x 50 mm	N/A	multilobated	NO	easily detatched	Ameloblastic fibroma	Enucleation with third molar	N/A	Lost to follow-up
3	2014	Mosqueda-Taylor A et al.	16	M	Latin America/Hispanic†	Asymptomatic	Buccal swelling	12 months	Left posterior mandible; angle	RL, UL, well defined	enclosing the crown of the third molar	NO	65 x 50 mm	N/A	multilobated	NO	embedded	Benign solid odontogenic tumour	Enucleation with third molar	NO	10 years
4	2014	Mosqueda-Taylor A et al.	3	F	Latin America/Hispanic†	Asymptomatic	Buccal and lingual bony expansion	22 months	Left posterior mandible; angle; ascending ramus	RL, BIL, well defined	enclosing the crowns of the second decidous and first permanent molars; absence of #20 tooth germ	YES (first decidous molar)	90 x 70 mm	N/A	multilobated	NO	easily detached	Ameloblastic fibroma	Enucleation with involved teeth	NO	9 years
5	2014	Mosqueda-Taylor A et al.	13	F	Latin America/Hispanic†	Asymptomatic	Buccal swelling	4 months	Left posterior mandible; angle; ascending ramus	RL, BIL, well defined	enclosing entirely the third molar	YES (first and second molars)	80 x 50 mm	N/A	multilobated	NO	embedded	Ameloblastoma; ameloblastic fibroma	Enucleation with third molar and 18-19	NO	3 years
6	2014	Mosqueda-Taylor A et al.	3	F	Latin America/Hispanic†	Asymptomatic	Buccal and palatal bony swelling	3 months	Left posterior maxilla; sinus floor; tuberosity	RL, UL, well defined	second decidous and first permanent molar	N/A	35 x 30 mm	N/A	multilobated	NO	easily detached	Benign solid odontogenic tumour	Enucleation with involved teeth	NO	6 months
7	2016	Slater LJ et al.	19	M	USA	Asymptomatic	Buccal and lingual bony expansion (thinning and resorption of lingual and inferior cortical plates)	N/A	Right posterior mandible	RL, UL, well defined	enclosing the crown of the third molar	YES (second molar)	N/A	25 x 19 x 15 mm	multilobated	NO	easily detached	N/A	Enucleation with third molar (no data on second molar)	NO	7 months
8	2016‡	Almazyad A et al.	15	F	USA (Hispanic)	Asymptomatic	Buccal swelling	N/A	Right posterior mandible; angle	RL, ML, well defined	enclosing the crown of the third molar	YES (first and second molars)	35 x 20 mm	N/A	N/A	NO	N/A	Dentigerous cyst	Enucleation with third molar	NO	3 months
9	2016‡	Almazyad A et al.	18	M	Mexico (Hispanic)	Asymptomatic	None	N/A	Right posterior mandible	RL, UL, well defined	enclosing the crown of a third molar	NO	17 x 12 mm	17 x 12 mm	multilobated	NO	easily detached	Dentigerous cyst	Curettage and third molar extraction	NO	20 months
10	2017	Ando T et al.	8	F	Japan	Asymptomatic	Buccal swelling	N/A	Left posterior maxilla; sinus floor	RL, UL, well defined	enclosing the crown of the first decidous molar	NO	N/A	N/A	multilobulated	NO	N/A	Dentigerous cyst, benign solid odontogenic tumour	Enucleation	NO	16 months
11	2017	Mikami T et al.	5	M	Japan	Asymptomatic	Buccal swelling, 1st decidous molar mobility	N/A	Right posterior mandible	RL, UL, well defined	association with the second decidous molar	YES (first decidous molar)	N/A	9 x 8 x 8 mm	nodule	NO	easily detached	N/A	Enucleation with involved teeth	NO	7 months
12	2018	Pardhe N and Bajpai M	17	M	India	Asymptomatic	Buccal swelling	6 months	Left posterior mandible; angle	RL, ML, well defined (scalloped upper margins)	enclosing the crown of the third molar	YES (second premolar, first and second molars)	N/A	N/A	N/A	N/A	N/A	Unicystic ameloblastoma	Enucleation with third molar; ID canal not preserved	NO	6 months
13	2018	Amer H et al.	2	M	Egypt	Painful	Buccal swelling	2 months	Right posterior mandible; angle; ramus	RL, ML, well defined	association with an impacted developing tooth	N/A	30 x 40 mm	N/A	N/A	YES	N/A	N/A	Enucleation with the impacted tooth	NO	2 years
14	2018	Bomfim BB et al.	4	M	Brazil (Black)	Asymptomatic	Buccal swelling; perforation of lingual cortical bone	8 months	Left posterior mandible	RL, UL, well defined	enclosing the crown of the second decidous molar; absence of #20 tooth germ; displacement of IAN canal	YES (first decidous molar)	30 x 20 mm	40 X 30 mm	multilobulated	NO	easily detached	Immature complex odontoma	Enucleation with incolved teeth	N/A	Lost to follow-up
15	2019	Teixeira LN et al.	13	F	Brazil (Black)	Asymptomatic	Buccal swelling	3 months	Left posterior mandible; angle; ascending ramus	RL, UL, well defined	enclosing the crown of the third molar	YES (at least, second molar)	N/A	N/A	N/A	N/A	N/A	Dentigerous cyst, odontogenic keratocyst, ameloblastoma	Enucleation with third molar (no data on other elements)	N/A	N/A
16	2019	Berdugo J and Bilodeau E	Preadolescent	M	N/A	Asymptomatic	Buccal swelling	N/A	Left posterior mandible; angle; ascending ramus	RL, UL, well defined	Absence of tooth 38	NO	22 x 20 mm	N/A	N/A	NO	Not applicable	Ameloblastic fibro-odontoma	Enucleation	N/A	N/A
17	2019	Sun Q et al.	10	M	South Korea	Asymptomatic	None	N/A	Left mandible, mesiolingual to the root of tooth 21	RL, UL, well defined	In close proximity to the root of the tooth	NO	5 x 5 x 5 mm	5 x 5 x 5 mm	nodule	NO	Not applicable	Simple bone cyst, periapical cemental dysplasia, paradental cyst	Enucleation	NO	12 months

^† One of the six original cases was reported in the Basque Country, Spain, European Union; ^‡ Event though tha paper was published in 2018, the cases were originaly described in two abstracts in 2016.

). A total of 17 cases of POT were identified in the literature. POT is a benign mixed epithelial and mesenchymal odontogenic tumour composed of a loose fibrous connective tissue resembling the dental papilla. The distinguishing feature of the neoplasm is the presence of a single layer of columnar cells resembling the inner enamel epithelium of the developing tooth that entirely covers the lesion peripherally.

4. Conclusions

Some issues about POT remain unclear and require future reports.

The description of the odontogenic epithelium covering the ectomesenchyme was often contradictory, while it remains debatable whether peripheral ameloblastic islands or hard dental tissue deposition can occasionally occur within the tumor [3,4].