Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare form arising within the jaws. PIOSCC is not related to the oral mucosa, presumably developing from remnants of the odontogenic epithelium. Because odontogenic cyst epithelium often transforms malignantly into PIOSCC, it could be misdiagnosed as odontogenic cyst based on a relatively ill-defined radiolucent lesion. Therefore, definite diagnosis is established from histological examination of biopsy samples taken during cyst enucleation in many cases. The present study is reported with a case of patient complaining of discomfort on his mandible. He was diagnosed as a putative dentigerous cyst and underwent a cyst enucleation treatment. After definite diagnosis as PIOSCC was established based on histologic findings, partial mandible resection and mandible reconstruction were performed. Up to the present, 10 months follow up of the patient showed satisfactory healing without recurrence and abnormal findings; thereby, we are reporting this case with literature review.