Primary intraosseous squamous cell carcinoma is a rare malignant tumour that exclusively arises within the jaws. Its diagnosis requires an appropriate clinical, imaging and histological correlation. The exclusion of primary oral mucosa lesions and metastatic disease is mandatory. We report an atypical imaging appearance of this uncommon entity, characterized by new bone formation and periosteal reaction that resemble sarcomatous or malignant odontogenic tumours. A comprehensive discussion on the embryological principles of primary intraosseous squamous cell carcinoma is also provided.