The objective of this retrospective study is to examine the clinical, imaging and pathologic features of 10 patients diagnosed with ‘primary intraosseous carcinoma (PIOC)’ at a single institution and to identify factors affecting the prognosis of PIOC patients. By proposing a new staging system based on tumor size, cortical bone deformation, neck metastasis and histologic grade, the study aims to address the lack of a distinct staging system, which has led to the mixed use of the classification for oral squamous cell carcinoma (OSCC). Furthermore, the study intends to suggest a treatment guideline based on the newly proposed staging system. By sharing the accumulated experience of treating PIOC patients at a single institution, the study seeks to contribute to more accurate diagnosis and appropriate treatment.