RESUMO
The primordial odontogenic tumor (POT) is a rare mixed odontogenic tumor composed of mesenchymal cells, columnar odontogenic epithelium, and fibromyxoid stroma affecting the posterior mandible of children and adolescents. Herein, we report 3 patients with POT and the clinicopathological features of POT previously reported in the literature. A 12-year-old, 19-year-old, and 4-year-old patient presented an asymptomatic swelling in the posterior maxilla and posterior mandible. Imaging exams revealed radiolucent lesions associated with unerupted teeth. The lesions were surgically removed, and the histopathological examination revealed spindle-to-ovoid mesenchymal cells in a fibromyxoid stroma surfaced by columnar odontogenic epithelial cells with reverse nuclear polarization. Deposition of mineralized tissue was observed. The final diagnosis was POT, and patients did not exhibit signs of recurrence. POT should be included in the differential diagnoses of intraosseous lesions in the posterior mandible in pediatric patients.
RESUMO
Although odontogenic lesions have been extensively described and studied, anomalous, challenging cases occasionally come to the attention of the pathologist. Here, we report the clinical and microscopic characteristics of an unusual cystic lesion of odontogenic origin. A 16-year-old male presented with swelling and pain to palpation of the right mandible as well as numbness of the right lower lip. Radiographically, the corresponding lesion was well-defined and radiolucent with internal radiopaque foci. It extended from the right first premolar posteriorly, approaching the angle of the mandible, and involved the mandibular first molar which was impacted and displaced. The second and third right mandibular molars were also impacted and displaced. The patient was treated by excisional biopsy under general anesthesia. The histopathologic examination revealed the presence of multicystic areas lined by a thin, non-keratinizing squamous epithelium that resembled the epithelial lining of a dentigerous cyst. In continuity with the cystic lining, areas of myxoid tissue reminiscent of dental papilla were observed. The myxoid tissue formed structures that were surfaced by an epithelium comprising a basal layer of ameloblast-like cells with reverse polarity of the nuclei. Above the basilar cells, additional layers of epithelial cells composed a structure resembling the enamel organ. Subjacent to the basilar ameloblast-like cells, a condensation of mesenchymal cells with polarized nuclei opposite to the ameloblast-like cells was present. These mesenchymal cells resembled odontoblasts. In addition, numerous mineralized structures amongst the odontogenic epithelial tissue were present. To date, the patient remains well and without evidence of recurrence after 36 months of follow-up.
Assuntos
Neoplasias Mandibulares/patologia , Neoplasias Embrionárias de Células Germinativas/patologia , Tumores Odontogênicos/patologia , Adolescente , Humanos , MasculinoRESUMO
Primordial odontogenic tumor (POT) was recently recognized in the 2017 World Health Organization (WHO) Classification as a distinct mixed odontogenic tumor most commonly observed in the posterior mandible of young patients. POT appears as an expansile radiolucency associated to an unerupted tooth. The aim of the present study was to perform a retrospective microscopic evaluation of pediatric odontogenic tumors diagnosed in an Oral Pathology Laboratory from Rio de Janeiro-Brazil, in order to reclassify potential cases as POT. From 150 cases of odontogenic tumors in children diagnosed in the last 50 years, one case filled the criteria for POT, being therefore better diagnosed as such. The patient was in the first decade of life and presented a well-defined expansile tumor in the posterior mandible, which had been initially diagnosed as immature complex odontoma. To the best of our knowledge, only 12 cases of POT have been reported in the English-language literature. We herein present an additional case of POT and review of its clinicopathological findings is offered.
Assuntos
Neoplasias Mandibulares/patologia , Tumores Odontogênicos/patologia , Pré-Escolar , Humanos , MasculinoRESUMO
Primordial odontogenic tumor (POT) is composed of variably cellular myxoid connective tissue, surrounded by cuboidal to columnar odontogenic epithelium resembling the inner epithelium of the enamel organ, which often invaginates into the underlying connective tissue. The tumor is delimited at least partially by a thin fibrous capsule. It derives from the early stages of tooth development. Syndecan-1 is a heparan sulfate proteoglycan that has a physiological role in several cellular functions, including maintenance of the epithelial architecture, cell-to-cell adhesion and interaction of cells with extracellular matrix, and with diverse growth factors, stimulating cell proliferation. Ki-67 is considered the gold standard as a cell proliferation marker. The aim of this study was to examine the expression of Syndecan-1 and Ki-67 proliferation index in POT and normal tooth germs to better understand the biological behavior of this tumor. Results showed that Syndecan-1 was more intensely expressed in subepithelial mesenchymal areas of POT, in a pattern that resembles the early stages of tooth development. The cell proliferation index (4.1%) suggests that POT is a slow growing tumor. Syndecan-1 expression in tooth germs in late cap and early bell stages was similar to POT, showing immunopositivity in subepithelial mesenchymal condensed areas. The immunohistochemical findings showed a pattern in which the population of subepithelial mesenchymal cells exhibited greater proliferative activity than the central portion of the dental papilla.