Primary intraosseous carcinoma (PIOC) is a rare odontogenic carcinoma defined as a squamous cell carcinoma arising within a jaw having no initial connection with the oral mucosa, and presumably developing from residues of the odontogenic epithelium. A 56-year-old patient who complained of delayed healing after extraction of upper left central incisor visited our department. The conventional radiographs showed a bony destructive lesion with illdefined margin and moth-eaten appearance. On the computed tomographic images, the lesion perforated the labial cortex of alveloar bone, elevated the left nasal floor superiorly, and perforated partially both nasal floor. The magnetic resonance images showed low signal intensity at T2 and T1 weighted images at the area and adjacent soft tissue. Histologically, there were irregular epithelial islands with cell atypia, nuclear hyperchromatism, pleomorphism, atypical mitosis. The final diagnosis was PIOC.