Abstract
BackgroundPrimary intraosseous carcinoma (PIOC), NOS is an odontogenic carcinoma with unknown etiology. Its diagnosis may be used when central jaw carcinoma cannot be categorized as any other type of carcinoma. Further information on this extremely rare tumor is needed to improve our understanding and evaluate the classification of odontogenic carcinomas.Case presentationWe herein presented two patients with PIOC, NOS with different clinical and histopathological features and analyzed gene mutations in these patients using next-generation sequencing (NGS). The typical PIOC, NOS case had many histopathological similarities to oral squamous cell carcinoma (OSCC), including the missense point mutations of TP53 Glu285Val, KDR Gln472His, and APC Pro1433Leu, which are similar to those in other cancers; however, no mutations were detected in the other patient with an atypical presentation of PIOC, NOS, which was derived from a precursor cystic lesion with similarities to both ameloblastic carcinoma and OSCC.ConclusionsGenetic analysis suggested that these two PIOC, NOS cases have different features and can be subcategorized.
Highlights
Primary intraosseous carcinoma (PIOC), NOS is an odontogenic carcinoma with unknown etiology
We reported a patient with ghost cell odontogenic carcinoma with a mutation in the CTNNB1 gene, suggesting that CTNNB1 gene mutations are one of the common features of lesions accompanied by ghost cell keratinization [11]
To reach a final diagnosis of primary intraosseous carcinoma (PIOC), NOS in case 1, we carefully considered a differential diagnosis of ameloblastic carcinoma
Summary
As described in the WHO Classification of Head and Neck Tumors, primary intraosseous carcinoma (PIOC), NOS is a central jaw carcinoma that cannot be categorized as any other type of carcinoma. A biopsy was performed, and the histopathological diagnosis was a cystic lesion suggestive of a keratocystic odontogenic tumor (Fig. 2a). The histopathology of the surgical enucleation specimen revealed an odontogenic keratocyst-like lesion in most parts (Fig. 2b). The lesion was enucleated, and the histopathology of the enucleated specimen revealed large nests or sheets of tumor cells The morphology of this tumor was composed of an ameloblastoma-like lesion and an oral squamous cell carcinoma (OSCC)-like lesion. The Ki-67 labeling index in the OSCC-like lesion was 20% (Fig. 2g, h) Based on these findings, this tumor was considered to be an intraosseous odontogenic carcinoma derived from a precursor odontogenic keratocyst. Based on the findings of the central jaw squamous cell carcinoma isolated from the oral mucosa, a final diagnosis of PIOC, NOS was made. The BRAF Val600Glu mutation was found in the patient with ameloblastoma (case 3)
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