Authors: Asma Almazyad, Nasser Almadan, Ahad Bin Juwaid, Abeer Alfadhel, Marwa Almarwan, Abdulsalam Aljabab
Categories: Case Report, Odontogenic, Paediatric, Primordial
Source: BMC Pediatrics
Authors: Asma Almazyad, Nasser Almadan, Ahad Bin Juwaid, Abeer Alfadhel, Marwa Almarwan, Abdulsalam Aljabab
Primordial odontogenic tumor (POT) is a rare, benign, mixed epithelial–mesenchymal neoplasm, histologically characterized by spindle- to stellate-shaped cells in a fibromyxoid stroma resembling dental papilla, bordered by columnar epithelium. It occurs mainly in children and adolescents, often in the posterior mandible, and radiographically presents as a well-defined radiolucency associated with unerupted teeth.
An 18-year-old male presented with asymptomatic swelling of the right mandible. Imaging revealed a well-demarcated unilocular radiolucency extending to the ascending ramus with cortical thinning and perforation. Under a provisional diagnosis of ameloblastoma, right mandibulectomy with plate reconstruction was performed. Histology showed spindle and stellate cells in a delicate collagenous stroma lined by columnar epithelium with reverse nuclear polarity and areas of solid and cystic epithelial proliferation, confirming POT.
We report the first case of POT in Saudi Arabia, managed surgically with no recurrence at seven-year follow-up. This case highlights the diagnostic challenges of POT and the importance of continued case documentation to guide recognition and management.
Primordial odontogenic tumor (POT) is a rare, benign, mixed epithelial-mesenchymal neoplasm of odontogenic origin. It was first described by Mosqueda-Taylor et al. [1] in 2014, reporting six cases. Shortly therefore, POT was recognized in the fourth edition of the World Health Organization (WHO) classification of odontogenic tumors in 2017 [2]. Since then, more than 42 cases have been documented in the English-language literature [3–7]. POT occurs almost exclusively during the first and second decades of life and demonstrates either a slight male predilection or no significant sex bias. Radiographically, it typically presents as a well-demarcated unilocular or multilocular radiolucency associated with a developing molar [8].
Histopathologically, POT is predominantly composed of spindled- to stellate-shaped cells proliferating within a fibromyxoid stroma, resembling dental papilla. The peripheral surface of the mass is lined by columnar epithelial cells exhibiting reverse nuclear polarity and clear to pale eosinophilic cytoplasm, reminiscent of ameloblastic epithelium [1]. Management typically involves enucleation or excision, usually accompanied by the removal of the associated tooth. In a few cases, more aggressive approaches such as mandibulectomy have been undertaken because the initial diagnosis was either odontogenic myxoma or ameloblastic fibroma [9]. Recurrence is exceedingly rare, with only a single case documented to date [10].
This report presents a new case of POT diagnosed at King Fahad Medical City, Riyadh, Saudi Arabia. To the best of our knowledge, this represents the first case reported in Saudi Arabia and the 39th case documented in the English-language literature.
A healthy 18-year-old Saudi male referred to King Fahad Medical City, Riyadh, Saudi Arabia, from Khamis Mushait hospital for asymptomatic swelling on the right side of the face with unknown duration, with a provisional clinical diagnosis of ameloblastoma. Clinical examination showed no discomfort or lip paresthesia with grade I mobility of the right permanent mandibular second molar. The patient reported no parental consanguinity, tobacco or nicotine use, or relevant family history of similar conditions. There were no additional findings in physical examination or laboratory data.
Panoramic radiograph revealed a well-demarcated, unilocular radiolucency measuring 3.5 cm x 2.5 cm associated with the crown of the developing right mandibular third molar (Fig. 1). There was a slight root resorption of the distal root of the right permanent mandibular second molar, and the radiolucency extended to the middle of the ascending ramus. Computed tomography with contrast showed an expansile unilocular radiolucency in the right posterior mandible extending from the right permanent second molar to the ascending ramus, measuring 3 cm x 5 cm (Fig. 2). There was cortical thinning and perforation.
Fig. 1Panoramic radiograph showed a well-demarcated, unilocular radiolucency measuring 3.5 cm x 2.5 cm in the right posterior mandible associated with the crown of the developing right third molar, extending to the right ramus, and causing mild resorption of the distal root of the right second molar
Fig. 2Axial view of computed tomography scan of expansile unilocular radiolucency with buccal expansion, cortical thinning, and perforation in the anterior buccal side of the lesion
An incisional biopsy was performed, and the tentative diagnosis was ameloblastoma. The patient underwent right hemi-mandibulectomy with plate reconstruction using fibular free flap from the right leg under general anesthesia. Postoperative healing was uneventful, with the patient experiencing no pain, infection, or paresthesia. Microscopically, the mass primarily consisted of highly cellular spindled cells in a delicate collagenous stroma, with multiple cystic-like spaces, and was covered by odontogenic epithelium with a papillary configuration (Fig. 3 -A). The epithelium comprised a single layer of columnar cells showing reverse nuclear polarity and pale eosinophilic cytoplasm, resembling ameloblastic epithelium (Fig. 3 -B). Other areas displayed stellate-like regions above the surface epithelium, and the underlying stroma exhibited densely cellular stellate-like and spindled cells in a delicate collagenous to myxoid matrix, resembling dental papilla (Fig. 3 -C). Additionally, the epithelium exhibited clear cytoplasm and eosinophilic hard tissue formation mimicking dentinoid deposits (Fig. 3 -D). In multiple areas of the tumor, the epithelial cells proliferate and form solid masses and cystic spaces within the underlying stroma. However, these were merely an extension of the surface epithelium rather than separate islands (Fig. 3 -E). Mitotic figures were not seen. Immunohistochemical staining revealed strong cytoplasmic CK19 expression in the epithelium, confirming an odontogenic origin (data not shown). Based on the histological evaluation, a diagnosis of POT was made. At the 4- and 7-year follow-up, there was no evidence of tumor recurrence. The fibular plate was stable and fused to the residual mandible, with no radiolucency identified. The soft tissues demonstrated complete healing with soft tissue overgrowth (Fig. 4). The patient is cleared for jaw rehabilitation, including vestibuloplasty and implant placement.
Fig. 3A. The tumor consisted of spindled and stellate-cell proliferation in delicately collagenous and myxoid stroma lined by odontogenic epithelium forming papillary surface configuration and cyst-like invaginations (H&E, original magnification X20). B. The lining epithelium was a single layer of columnar epithelium exhibiting reverse nuclear polarity, pale eosinophilic cytoplasm, and cytoplasmic vacuolization (H&E, original magnification X200). C. There were areas of the epithelium that showed a prominent papillary configuration with prominent, clear cytoplasm. The stroma is ectomesenchymal, exhibiting high cellularity of stellate-like cells in myxoid stroma (H&E, original magnification X100). D. Focally, there was eosinophilic hard tissue formation within the clear cytoplasm of the epithelium. This was reported previously in POT (H&E, original magnification X100). E. There were solid epithelial invaginations, which occasionally show cyst-like spaces (H&E, original magnification X40)
Fig. 4A- Panoramic radiograph of the patient, 4 years post-surgery, with no evidence of recurrence. B- Panoramic radiograph of the patient, 7 years post-surgery, with no evidence of recurrence
POT is a rare, benign odontogenic neoplasm composed of epithelial and ectomesenchymal components, the latter resembling dental papilla [1]. First described by Mosqueda-Taylor et al. in 2014 [1], it was subsequently recognized as a distinct entity in the 2017 and 2022 WHO classification of odontogenic tumors [2, 11, 12]. Despite increasing awareness, POT remains exceedingly uncommon, with only approximately 38 well-documented cases reported worldwide (Table 1) [3–7]. Our case represents the first reported occurrence in Saudi Arabia, thereby expanding the geographic distribution of this entity and emphasizing the importance of regional reporting to improve global epidemiology.
Table 1Summary of clinical and radiographic features of published cases of POTAge in years / genderLocationRadiographic presentationTreatmentFollow upMosqueda-Taylor et al. 2014 [1]18/MLeft posterior mandibleRL, UL, well defined, 4.5 × 4.0 cm, surrounding the crown of the third molarEnucleation and tooth extraction 20 years, NED16/MLeft posterior mandibleRL, UL, well defined, 5.5 × 5.0 cm, surrounding the crown of the third molar with jaw expansionEnucleation and tooth extraction LFU16/MLeft posterior mandibleRL, UL, well defined, 6.5 × 5.0 cm, surrounding the crown of the third molarEnucleation and tooth extraction 10 years, NED3/FLeft posterior mandibleRL, BL, well defined, 9.0 × 7.0 cm, surrounding the crowns of the second deciduous and first permanent molars with jaw expansion, and tooth displacementEnucleation and tooth extraction 9 years, NED13/FLeft posterior mandibleRL, BL, well defined, 8.0 × 5.0 cm, surrounding the crown of the third molarEnucleation and tooth extraction 3 years, NED3/FLeft posterior MaxilaRL, UL, well defined, 3.5 × 3.0 cm, surrounding the crowns of second deciduous and first permanent molars with jaw expansion and tooth displacementEnucleation and tooth extraction 6 months, NEDSlater et al. 2016 [13] 19/MRight posterior mandibleRL, UL, well defined, 2.5 × 1.9 cm, surrounding the crown of the third molar with jaw expansion and tooth resorptionExcision and tooth extraction7 months, NEDAndo et al. 2017 [14]8/FLeft posterior MaxillaRL, UL, well defined, 1.5 × 1.5 cm, associated with crown of the first deciduous molar with jaw expansion and tooth displacementExcision and tooth extraction7 months, NEDMikami et al. 2017 [15]5/MRight posterior mandibleRL, UL, well defined, 1.5 × 0.5 cm, associated with crown of second deciduous molarEnucleation16 months, NEDAmer et al. 2018 [16]2/FRight posterior mandibleRL, ML, well defined, 3.0 × 4.0 cm, associated with the crown of deciduous molar with jaw expansionExcision and tooth extraction7 months, NEDPardhe et al. 2018 [17]17/MLeft posterior mandibleRL, ML, well defined, 9.0 × 5.0 cm associated with the crown of the third molar with multiple teeth resorptionExcision and tooth extraction2 year, NEDAlmazyad et al. 2018 [8, 10]15/FLeft posterior mandibleRL, ML, well defined, 3.5 × 2.0 cm, associated with the crown of the third molar with cortical perforation and tooth resorptionEnucleation and tooth extraction Recurrence after 4 years18/MLeft posterior mandibleRL, UL, well defined, 1.2 × 0.7 cm, associated with the crown of the third molarExcision and tooth extraction20 month, NEDBomfim et al. 2019 [18]4/MLeft posterior mandibleRL, UL, well defined, 3.0 × 2.0 cm, associated with the crown of the deciduous second molar with jaw expansion and tooth resorptionCurettage and tooth extraction20 months, NEDTeixeira et al. 2019 [19]13/FLeft posterior mandibleRL, UL, well defined, 3.0 × 4.0 cm, associated with the crown of the third molarExcisionNot mentionedPoomsawat et al. 2019 [20]17/FLeft posterior mandibleRL, UL, well defined, 3.0 × 2.5 cm associated with the crown of the third molar with internal radiopaque materialPartial mandibulectomy18 months, NEDPassador-Santos F, et al. 2020 [21]16/FRight posterior mandibleRL, UL, well defined, 3.0 × 5.0 cm associated with second molar with multiple radiopacitiesEnucleation and curettage3 years, NEDZeng M, et al. 2020 [22]2/MRight posterior maxillaRL, UL, well defined, 2.5 × 2.2 cm, associated with the crown of first deciduous molar with jaw expansion and perforationEnucleation11 months, NED12/FRight posterior maxillaRL, UL, well defined, 3.5 × 2.5 cm, associated with the crown of the third molar with multiple teeth resorptionExcision13 year, NEDGodoy H et al. 2021 [23]6/MLeft anterior maxillaRL, UL, well defined, associated with left central incisorEnucleation and tooth extraction 10 years, NEDBashar A, et al. 2021 [24]13/MLeft anterior maxillaRL, UL, well defined, 3.2 × 3.1 cm, associated with unerupted canineExcision and tooth extractionNot mentionedDelgado-AzaAero WA, et al. 2021 [25]12/FRight posterior mandibleRL, UL, well defined, 3.5 × 3.0 cm, associated with the crown of second premolar with tooth displacement and resorptionEnucleation and tooth extraction 15 months, NED13/FLeft posterior mandibleRL, UL, well defined, 2.5 × 2.0 cm, associated with the crown of third molarEnucleation5 years, NEDKayamori K, et al. 2021 [26]10/MRight posterior maxillaRL, UL, well defined, 1.7 × 1.5 × 1.0 cm, associated with the crown of deciduous second molar with jaw expansion, and internal radiopaque materialEnucleation30 months, NEDNaina S, et al. 2021 [27]14/MRight anterior maxillaRL, UL, well defined, 3.0 × 2.0 cm, associated with crown of the canine with jaw expansionExcision3 years, NEDPozuelo Arquimbau L, et al. 2022 [28]14/MRight posterior maxillaRl, UL, well defined, 5.0 × 5.0 cm, associated with the crown of the third molar with root resorptionExcision and tooth extraction1 year, NEDVijayan S, et al. 2023 [29]12/FRight posterior mandibleRL, UL, well defined, in the area of missing third molar with calcificationsExcisionNot mentionedSun Xiaoqin, et al. 2022 [30]26/MLeft posterior mandibleMixed, UL, well defined, associated with the third molar with absorption of the bone cortex, impingement of the mandibular canal and resorbtion of adjacent teethExcision and tooth extraction5 months, NEDSuresh R, et al,2023 [31]3/FLeft posterior mandibleMixed, ML, well defined, associated with developing teeth and extending upwards into the posterior zygomatic arch, infra‑temporal fossa and orbital floor causing resorbtionIncisional biopsy onlyNot mentionedCavalcante IL, et al. 2023 [32]12/FLeft posterior MaxilaRL, UL, well defined, associated with the first permanat molar with displacement to the orbital floorExcision1 year, NED19/FRight posterior mandibleRL UL, well defined, associated with the third molar with resorbtion of adjacent toothpartial madibulectomy1 year, NEDAyyappan K, et al. 2023 [33]8/MLeft posterior mandibleRL, UL, well defined, associated with first and second molarsEnucleation and tooth extraction 7 months, NED8/MRight posterior mandibleRL, UL, well defined, on the distal aspect of follicular space of the second permanent molarEnucleation and tooth extraction 7 months, NEDQureshi M FH, et al. 2024 [34]5/MLeft posterior MaxilaMixed, UL, well defined, centered in the left maxillary sinus with thinning of the maxillary bone extending up to the retromolar trigone regionLefort I surgery6 months, NEDDwivedi D, et al. 2025 [7]17/MLeft posterior mandibleMixed, UL, well defined, 4.2 × 3.3 × 3.3, surounding an impacted first molarEnucleation with peripheral osteotomy and tooth extractionNot mentionedFigueredo Junior JM et al. 2025 [4]10/MAnterior mandibleRL, UL, well defined, surrounding with the right lower canine with cortical perforation and displacement of teethExcision and tooth extractionNot mentionedSebastian, S et al. 2025 [5]17/MRight posterior mandibleRL, UL, well defined, on the mesial aspect of supernumerary toothExcision and tooth extraction7 months, NEDPresenet case18/MRight posterior mandibleRL, UL, well defined, 3.0 × 5.0 cm, associated with the crown of the third molarwith cortical thining, perforation and tooth resorptionMandibulectomy with plate reconstruction7 years, NEDRL radiolucent, UL unilocular, NED no evidence of disease, LFU lost to follow-up, BL biloculated, ML Multilocular
The largest systematic review of POT, which included 36 cases, confirmed that POT predominantly affects children and adolescents, with a mean age of 11.4 years and a slight male predilection (male-to-female ratio 1.18:1) [3]. The posterior mandible, particularly in association with unerupted molars, was the most frequently affected site (61.1%), similar to our reported case. However, anterior mandible cases have been reported [4]. Radiographically, most cases appear as well-defined unilocular radiolucencies (83.35%), while multilocular or bilocular presentations are not unusual [3, 35]. Common associated features include cortical thinning (66.7%), cortical expansion (58.3%), tooth displacement (52.8%), and root resorption (44.4%), with cortical perforation present in about 20–25% of cases [3]. A minority (13.9%) shows internal calcification or mixed radiolucent–radiopaque features, reflecting dystrophic calcification, enameloid, or dentinoid [20, 30]. The radiographic findings in our patient, including cortical perforation and root resorption, were consistent with the reported spectrum. Although focal hard tissue was present histologically, no radiopaque component was detected radiographically, a discrepancy previously attributed to microscopic calcifications being insufficient to produce detectable radiographic changes.
Histopathologically, POT is characterized by a primitive fibromyxoid stroma resembling dental papilla, bordered by a single layer of columnar cells with reverse nuclear polarity and pale eosinophilic cytoplasm [1]. Our case also demonstrated focal dentinoid-like deposits, a rare feature documented in approximately 2–3% of cases [3], further expanding the morphologic spectrum. Recent reports have emphasized that POT exhibits greater histological variability than originally described. Dwivedi et al. [7] documented the first hybrid POT-dentigerous cyst, with conspicuous enameloid and dentinoid deposition, and proposed updated diagnostic criteria. Figueredo et al. [4] described an anterior mandibular POT initially misdiagnosed as ameloblastoma and ameloblastic fibroma, highlighting the frequent diagnostic pitfalls associated with this tumor [23]. Similarly, our case was also misdiagnosed as ameloblastoma, a reflection of the tumor’s relatively recent description and the consequent lack of familiarity among pathologists at the time.
POT presents significant diagnostic challenges because of its morphologic overlap with several odontogenic lesions, leading to bidirectional misdiagnosis. On one hand, many true POTs have been mistaken for ameloblastoma, ameloblastic fibroma, or odontogenic myxoma [20, 36]. For example, Figueredo et al. [4] described an anterior mandibular POT that was first misdiagnosed as ameloblastoma and later as ameloblastic fibroma. These errors often led to unnecessarily aggressive management, such as segmental or hemi-mandibulectomy. On the other hand, several lesions reported as POT in the literature have subsequently been reinterpreted as developing odontoma, dental follicle, or dental papilla, entities that can closely resemble POT histologically but lack its defining features [5, 37–41]. Developing odontomas may show primitive dental papilla-like stroma with enamel or dentin induction, dental papilla mimics the ectomesenchymal stroma of POT but is not surfaced by epithelium, and hyperplastic dental follicles may present with pericoronal radiolucencies without the hallmark reverse nuclear polarity of POT. Careful recognition of POT’s key clinical and histological features is critical to avoid both under-recognition and over-reporting of this rare tumor.
POTs are primarily treated with conservative surgical methods, with enucleation and curettage being the most common approaches, followed by excision [3]. In one reported case, treatment was declined due to religious beliefs [31]. The mean follow-up duration was 36.4 months, with follow-up achieved in 80.5% of patients, and only one case demonstrated recurrence after four years [10]. This case holds particular significance as the first documented diagnosis of POT in Saudi Arabia. Initially misdiagnosed as ameloblastoma, the lesion’s aggressive radiographic characteristics warranted mandibulectomy with subsequent reconstruction. Definitive diagnosis was established through comprehensive clinical, radiographic, and histopathological evaluation. The absence of recurrence at seven years postoperatively reinforces the favorable prognosis associated with POT. This report adds important data to the sparse global literature on this rare odontogenic tumor. It underscores the critical need for accurate diagnosis to ensure appropriate treatment planning and to prevent overtreatment. Our case is a single case report, which generally restricts the generalizability and precludes definitive treatment recommendations. In addition, postoperative rehabilitation (vestibuloplasty and implant placement) has not yet been completed, limiting assessment of long-term functional and rehabilitative outcomes.
POT is a rare odontogenic neoplasm that may pose diagnostic challenges due to its histopathologic variability and potential for misinterpretation. Recent reports describing uncommon presentations, including association with dentigerous cysts, anterior mandibular involvement, and hard tissue formation, underscore the importance of careful morphologic assessment. The present case adds to the limited published literature, represents the first reported case from Saudi Arabia with long-term follow-up, and illustrates the potential consequences of diagnostic uncertainty on surgical management. Continued reporting of well-documented cases may help improve recognition of this entity and support future refinements in diagnostic criteria to promote appropriate clinical management.