Squamous odontogenic tumor. Report of three cases including the first extraosseous case

Exceptional Evolution of a Squamous Odontogenic Tumor in the Jaw: Molecular Approach

A squamous odontogenic tumor (SOT) is an epithelial locally benign neoplasia derived from the periodontium of the jaws. It is considered a lesion of low incidence. Predominantly, it affects the mandible, although both jaw bones may be involved. Here, we discuss the malignant clinical evolution of an SOT lesion in an 80-year-old female patient. The patient exhibited an expansive triangular lesion at the inferior right quadrant. Surgery was performed and an SOT was diagnosed (2019). Two years after, the lesion grew, and the analysis of the biopsy revealed SOT malignization with pleomorphic atypical squamous cells, characteristics of a squamous cell carcinoma (2021). Massive DNA sequencing of formalin-fixed-paraffin-embedded specimens of the initial and relapsed tumors indicated pathogenic mutations in RET and POLE genes in both tumors, loss of ALK, and gain of CDKN1B and MAP2K in the relapse. In addition, the clinical, radiographic, and microscopic features of this neoplasm are discussed and compared with those already published. The case presented contributes to the better understanding of this SOT tumor entity and to indicates its malignant evolution, together with its biological behavior and its histologic, clinical, and radiographic features. Also, it aims to stress the importance of deeper genetic analyses in rare diseases to uncover mutations that help to select a personalized treatment.

Benign Odontogenic Tumours

Odontogenic tumours of the maxillofacial region presents with a large number of histologic patterns and are derived from the primordial tooth forming tissues. They can occur most commonly in mandible and maxilla. The recent WHO classification helps in developing the appropriate treatment plan and categorizing the tumours. The present chapter deals with various benign odontogenic tumours with their clinical presentation and management in detail, based on clinical scenarios.

Squamous Odontogenic Tumor: Review of the Literature and Report of a New Case

PURPOSE

Squamous odontogenic tumor (SOT) is a rare, benign, locally infiltrative odontogenic tumor of the gnathic bones. It is composed of islands of bland, well-differentiated squamous epithelium of varying shape and size. Because of histologic overlap, SOT has often been overdiagnosed as ameloblastoma and squamous cell carcinoma. It thus becomes important to understand the clinical, radiologic, histopathologic, and treatment characteristics of this tumor.

MATERIALS AND METHODS

Using the PubMed and Google Scholar databases, we searched for reported cases of SOT published in the English-language literature. We were able to retrieve 49 acceptable cases and perform a comprehensive literature review of the intraosseous SOTs, with emphasis on their clinical, radiographic, and pathologic characteristics, as well as treatment strategies. In addition, we present an additional case of SOT affecting the posterior mandible in a 44-year-old female patient.

RESULTS

The tumor in the posterior mandible in our patient was accompanied by acute pain and treated by enucleation. Histopathologic evaluation showed variably sized islands of benign squamous epithelium scattered in a fibrous stroma, consistent with the diagnosis of an SOT. Uneventful healing was noted at the 1-month postoperative appointment. However, the patient was lost to long-term follow-up. Our literature review showed that the average age at the time of diagnosis of SOT is 34.2 years. Men and women are equally affected, and the tumor does not show a predilection for either jaw bone. The most common locations are the anterior maxilla and posterior mandible. Most SOTs are treated conservatively by enucleation or curettage, whereas aggressive or recurrent tumors require radical resection.

CONCLUSIONS

Careful evaluation of the excised specimen, with immunohistochemical investigations, may prove rewarding in differentiating an SOT from other odontogenic neoplasms and thus minimize the patient's chances of undergoing an unnecessary aggressive intervention.

Squamous odontogenic tumor and squamous odontogenic tumor-like proliferations in odontogenic cysts: An updated analysis of 170 cases reported in the literature

PURPOSE

To integrate the available data published on squamous odontogenic tumors (SOT) and squamous odontogenic tumor-like proliferations in odontogenic cysts (SOT-LPOC) into a comprehensive analysis of their clinical/radiologic features.

MATERIALS AND METHODS

An electronic search was undertaken in January 2017. Eligibility criteria included publications having enough clinical/radiological/histological information to confirm a definite diagnosis.

RESULTS

A total of 74 publications reporting 110 SOTs (102 central, 8 peripheral) and 60 SOT-LPOC were included. Compared to SOT-LPOC, SOT showed lower mean age, no preference regarding maxilla or mandible localization, significant association with cortical bone perforation, multilocular radiographic appearance, and mobility of the tooth/teeth associated with the lesion. While 5 recurrent SOT were reported after enucleation, no recurrent SOT-LPOC was found.

CONCLUSIONS

SOT shows a more aggressive biologic behavior than SOT-LPOC, which supports the hypothesis that the two lesions are distinct clinicopathological conditions.

A squamous odontogenic tumor following an orthodontic micro-screw: A rare case report and review of the literature

We reported a very rare case of squamous odontogenic tumor(SOT) in a 23-year-old female. The tumor arose after an implanting operation of an orthodontic micro-screw, and was definitely diagnosed by the histopathological examination. Based on the case report and a review of the literature, we discussed about the general features, differential diagnosis and pathogenesis of SOT.

Surgical Management of an Aggressive Multifocal Squamous Odontogenic Tumor

Squamous odontogenic tumor is a rare benign epithelial odontogenic tumor of the jaw. Most are solitary lesions, although rare multifocal lesions have been described. Maxillary lesions have more aggressive behavior. Because of their benign character, these lesions are usually treated using a conservative surgical approach with curettage and surgical enucleation. This report describes the case of a 29-year-old woman with multifocal lesions who was initially treated with conservative surgical therapy. Early recurrence 6 months after surgery prompted more aggressive resection. This case is discussed in the context of current evidence related to the epidemiology, etiology, diagnosis, and therapy of squamous odontogenic tumors.

Clinicopathological characteristics of desmoplastic ameloblastoma: A systematic review

The aim of the present review was to systematically present the clinicopathological data of desmoplastic ameloblastoma (DA) from articles published in the literature. A comprehensive search of the databases (PubMed, Medline, SCOPUS, Web of Science, and Google Scholar) for published articles on DA was conducted. A total of 238 cases were identified and analyzed from 76 published papers. DA showed a slight male predilection (male: female=1.07:1) with a predominance in the fourth and fifth decades of life. Mandibular involvement (52.55%) was most commonly seen with a marked tendency for the anterior region (mandible: 40.9%, maxilla: 48.07%). The size of the lesion ranged from .5 cm to 20.4 cm, with the majority of cases measuring more than 3 cm in size (53.84%). Radiologically, most of the lesions presented mixed radiolucency and radiopacity (62%), and root resorption was observed in only seven cases. The majority of the lesions showed ill-defined margins upon radiographic examination (65.78%). Most of the cases were treated with resection (78.57%), and five of the 10 recurrent cases were treated by enucleation/curettage. DA is characterized by the unique presentation of clinicopathological parameters. It is not possible to comment on its aggressive/recurrent nature and best treatment modality due to inadequate follow-up data.

Multicentric Squamous Odontogenic Tumor: A Case Report and Review of the Literature

Squamous odontogenic tumor (SOT) is a rare benign epithelial odontogenic neoplasm of the jaws. Both intraosseous and peripheral SOTs have been described in the English language literature. While most intraosseous SOTs occur as solitary lesions, a multicentric variant has also been previously described. Although the radiographic and microscopic features are identical for both solitary and multicentric clinical presentations, there are three significant differences between them. More specifically, multicentric SOT presents at an earlier age (third decade of life), has a slightly higher male to female ratio than the solitary type and has a marked predilection for African-Americans. Here we document the eighth reported case of multicentric SOT, which was diagnosed in a 43-year-old African-American male. In addition, we feature focal sebaceous metaplasia, a heretofore unknown microscopic feature of SOT. Clinical, radiological, and histopathological findings are discussed. The differential diagnosis, biological behavior and management modalities for SOT are also addressed.

Recurrent squamous odontogenic tumor: A case report and review of the literature

Squamous odontogenic tumors (SOTs) are benign, locally infiltrative neoplasms that localize to the periodontium. In total, <50 cases have been reported since the first description of SOTs in 1975. Although the exact etiology of SOTs is unknown, the tumors are considered to derive from the epithelial cell rests of Malassez. SOTs are characterized by radiological and clinical signs and symptoms, including pain with increased sensitivity in the affected area, bone expansion and increased tooth mobility. The present study describes the case of a patient that experienced numerous SOT recurrences and also discusses recommendations for treatment. A locally invasive mandibular SOT was identified in a Caucasian 41-year-old female patient. The treatment involved recommended conservative surgery, including local curettage. In addition, 49 cases published in the literature were reviewed to assess the treatment strategies. The present patient experienced two recurrences of the tumor during the 6-year follow-up period. Ultimately, the vitality of the adjacent teeth was compromised. An apicoectomy with a small amount of resection of the marginal bone was necessary. In >50% of the reported cases of SOT in the literature the adjacent teeth were extracted. The present case of SOT and the associated literature were also discussed. It was concluded that the treatment of choice appears to be a conservative surgical removal, but the successful management of SOTs often requires the removal of the adjacent teeth.

Squamous Odontogenic Tumor: Literature Review Focusing on the Radiographic Features and Differential Diagnosis

Since its first publication in 1975, the squamous odontogenic tumor remains the rarest odontogenic lesion, with around 50 cases in the English-language literature in which the microscopic characteristics are frequently very well demonstrated. However, articles which discuss the radiographic aspects are scarce, especially with emphasis on the differential diagnosis. The present treatise proposes an assessment of jaw lesions with the same radiographic characteristics of the squamous odontogenic tumor to clarify the main findings for dental clinicians during routine diagnosis.

Squamous odontogenic tumor with unusual localization and appearance: a rare case report

Squamous odontogenic tumor is a rare benign neoplasm and may affect multiple sites in the mouth. SOT was first described by Pullon et al. (1975). Since then, there have been less than 50 reported cases. The tumor is often asymptomatic, although it can present with symptoms of pain and tooth mobility. We report a case of SOT occurring in a 26-year-old female in the anterior mandible with unusual localization and appearance.

Squamous odontogenic tumor: A case report and review of literature

The squamous odontogenic tumor (SOT) is a rare, benign, locally infiltrative neoplasm of the jaws that appears to originate from the rests of Malassez, gingival surface epithelium or from remnants of the dental lamina. SOT was first described by Pullon et al. (1975). Since then there has been paucity in the number of reported cases, especially in the Indian subcontinent. The tumor is often asymptomatic, although it can present with symptoms of pain and tooth mobility. The characteristic radiographic appearance is that of a triangular-shaped unilocular radiolucency associated with the roots of erupted, vital teeth and has a predilection for the anterior maxilla and the posterior mandible. Histologically, the tumor is characterized by the formation of variably sized nests and cords of uniform, benign-appearing, squamous epithelium with occasional vacuolization and keratinization. We report a case of SOT occurring in a 58-year-old male in the anterior mandible with unusual localization and appearance.

'A harmless but confusing tumour on the anterior maxilla'

Squamous odontogenic tumour (SOT) is a very rare benign neoplasm probably arising from rests of Malassez. Patients may present with an increase in the volume of the maxilla or mandible, tooth mobility, ulceration of the oral soft tissue, painful symptoms and tooth displacement. Radiographic features of SOT consist of a triangular-shaped radiolucent lesion adjacent to the roots of teeth. Histologically, care should be taken not to misdiagnose this condition as acanthomatous ameloblastoma or well-differentiated squamous cell carcinoma. The authors are presenting a case of a 65-year-old male patient who presented with a painless swelling and diagnosed to be having SOT.

Squamous odontogenic tumor of the mandible: a case report demonstrating immunoexpression of Notch1, 3, 4, Jagged1 and Delta1

Background

Squamous odontogenic tumor (SOT) is a rare benign odontogenic epithelial neoplasm. A slow-growing painless expansive swelling is the common presenting symptom. Histopathologically, SOT can be easily misdiagnosed as an acanthomatous ameloblastoma. Although Notch receptors and ligands have been shown to play a role in cell fate decisions in ameloblastomas, the role of these cell signaling molecules in SOT is unknown.

Case report

This paper describes a case of SOT affecting the anterior mandible of a 10-year-old Indian female. The patient was treated by local surgical excision and there has been no follow-up clinical record of recurrence 5 years after primary treatment. Histopathological examination revealed a solid, locally-infiltrative neoplasm composed of bland-looking squamatoid islands scattered in a mature fibrous connective tissue stroma and the diagnosis was SOT. Immunohistochemical evaluation showed positive reactivity of varying intensity in the neoplastic epithelial cells for Notch1, Notch3, Notch4, and their ligands Jagged1 and Delta1. Expression patterns showed considerable overlap. No immunoreactivity was detected for Notch2 and Jagged2.

Conclusions

Present findings suggest that Notch receptors and their ligands play differential roles in the cytodifferentiation of SOT.

Aggressive maxillary squamous odontogenic tumour in a child: histological dilemma and adaptative surgical behaviour

A case of a maxillary osteolytic tumour is described in a 9-year-old boy. Histological analysis led to an initial diagnosis of benign squamous odontogenic tumour, although this was not straightforward due to swelling, and cellular pseudo-malignant and non-specific signs. Because of the young age of the patient, a local surgical tumourectomy was first chosen with respect to the mixed dentition. For 10 months, the evolution was satisfactory. Then, a very aggressive tumoural recurrence with lip and palate infiltration led to doubts as to the histologic nature of the tumour. Efficient collaboration between several specialized pathologist teams finally confirmed that this was a squamous odontogenic tumour but in a very aggressive form. Radical surgery was then carried out.

Relative frequency of peripheral odontogenic tumors: a study of 45 new cases and comparison with studies from the literature

BACKGROUND

Peripheral (extraosseous) odontogenic tumors are rare, and reports in the literature have mainly been single case reports or a small series of cases. The aim of this study was to determine the relative frequency of peripheral (extraosseous) odontogenic tumors relative to one another and relative to their central (intraosseous) counterparts in an oral pathology biopsy service and to compare these data with information available in the literature.

METHODS

The files of the Pacific Oral and Maxillofacial Pathology Laboratory of the University of the Pacific, San Francisco, CA, USA, served as the source of material for this study. Files were systematically searched for all cases of peripheral odontogenic tumors (POTs) during a 20-year-period.

RESULTS

There were 91,178 cases accessed in which central and POTs were identified in 1,133 (1.24%), central tumors in 1,088 (1.2%), and peripheral tumors in 45 (0.05%). Peripheral tumors accounted for 4% of all 1133 central and POTs. Peripheral odontogenic fibroma (PODF) was the most common of the 45 POTs accounting for 51.1% (23 cases) followed by peripheral ameloblastoma (PA) 28.9% (13 cases) and peripheral calcifying cystic odontogenic tumor (PCCOT) 13.3% (six cases). Peripheral calcifying epithelial odontogenic tumor, peripheral ameloblastic fibroma, and peripheral ameloblastic carcinoma were also identified--each comprised 2.2% (one case each). PODF was more common than its central counterpart by a 1.4:1 ratio. This was the only peripheral tumor that was more common than its central counterpart. PA accounted for 9.3% of all ameloblastomas and PCCOT for 26% of all calcifying cystic odontogenic tumors.

CONCLUSION

There is only scarce information in the literature on the relative frequency of POTs. Additional studies should be conducted to determine the true relative frequency. To ensure accuracy, pathologists with experience in the field of odontogenic tumors should conduct these studies. Intraosseous tumors that perforate through the bone to the gingival tissue, clinically presenting as 'peripheral tumors' should be excluded.

Peripheral odontogenic tumor: a clinicopathologic study of 30 cases. General features and hamartomatous lesions

BACKGROUND

Peripheral odontogenic tumors (POT), either neoplastic or hamartomatous, are rare. This study briefly summarizes the general features of POT and selectively reviews the histomorphologic spectrum of under-recognized hamartomatous lesions that we have designated peripheral odontogenic hamartomas (POH) in order to shed more light into the pathogenesis of POT.

METHODS

Archival material accessioned at our institutions between 1970 and 2004 was systematically searched to identify examples of POT/POH.

RESULTS

Among 39 660 biopsies, we retrieved 25 cases of 'classical' POT and five cases of 'unique' POH. Odontogenic fibroma and ameloblastoma were by far the most common. Of POH, two purely epithelial lesions showed multiple strands of basaloid rests [odontogenic gingival epithelial hamartoma (OGEH)] and a conglomerate of polyhedral epithelium, ghost cells and concentric calcifications (calcifying epithelial odontogenic tumor-like hamartoma), respectively. OGEH and peripheral squamous odontogenic tumor (PSOT) deserve to be a related entity. In two types of mixed POH, ectomesenchymal elements appeared juxtaposed to the squamous lining (gingival cyst-like organoid hamartoma) and ghost cells aggregated in the enamel organ of a microdont (peripheral odontoma). None of POH exhibited continuity with the surface epithelium.

CONCLUSION

On the basis of this relatively limited series of cases, POH, to conceptualize a unified histogenetic source, are speculated to arise from the soft-tissue remnants of dental lamina. Gingival rests of Serres seem to retain the ability to pursue epithelial-ectomesenchymal interactions that are necessary leading to odontoma formation.

Intraosseous squamous cell carcinoma arising in association with a squamous odontogenic tumour of the mandible

We report a rare occurrence of intraosseous squamous cell carcinoma (SCC) arising in association with a squamous odontogenic tumour (SOT), which had not previously been documented in the literature. A 53-year-old man had, for 5 years, a well-demarcated radiolucency attached to the impacted third molar of the mandible. The enucleated specimen had a characteristic pattern of SOT, but in which a few epithelial islands showed atypical features suggestive of SCC. Intense p53-, proliferating cell nuclear antigen- and Ki-67-positive cells were detected in carcinoma areas. Within 2 months, aggressive bone destruction showing typical findings of intraosseous SCC appeared. The present tumour is presumably a malignant variant of SOT.

Squamous odontogenic tumour: report of two cases

Squamous odontogenic tumour is a benign odontogenic tumour composed of a well-differentiated squamous epithelium immersed in a fibrous connective tissue stroma. It is a rare tumour and a recent literature review yielded only 36 cases. Two cases of squamous odontogenic tumour are presented, 1 located in the maxilla and the other in the mandible: 1 of these cases showed a periodontal involvement. The radiographic picture was fairly characteristic in 1 case, with a radiolucent lesion between the roots of the second mandibular premolar and the first molar, while, in the other case, it was possible to observe the presence of a lesion located at the apex of a molar. The tumours were enucleated, and no recurrences were observed after 5 years.

Squamous odontogenic tumor (SOT): a benign neoplasm of the periodontium. A review of 36 reported cases

True neoplasms are rarely localised to the periodontium. However, early recognition and diagnosis of neoplastic lesions resides within the realm of responsibility of the dentist. In recent years, a number of odontogenic tumors has been described characterized by an occurrence on the gingiva or in the intrabony part of the periodontium. One such neoplasm, the squamous odontogenic tumor (SOT) originally described 20 years ago is now a well-recognized entity localized to the periodontium, be it in the periodontal ligament or in the gingivae. A review of 36 acceptable cases of this tumor published sofar, forms the basis of the present paper.

Neuroepithelial hamartoma of the oral cavity

We report a previously undescribed gingival lesion composed of squamous epithelial islands in close association with bundles of nonmyelinated nerves. A review of the pertinent literature is presented and the histologic differential diagnosis is discussed. We suggest the term neuroepithelial hamartoma for this lesion.

Squamous odontogenic tumor

The squamous odontogenic tumor is almost exclusively an intraosseous lesion of the jaw bones. Only 1 extraosseous variant has been reported. The tumor is histologically benign, with only occasional recurrences after surgical removal. Malignant alteration is unknown, but the lesion must be distinguished from intraosseous squamous cell carcinomas.