A primary intraosseous squamous cell carcinoma case report and literature review. The new WHO classification

Abstract Aim: Cyst-like lesions in the mandible rarely develop into malignancies, and the re- ported incidence is between 0.3% and 2%. The present study describes a rare case of primary intraosseous squamous cell carcinoma of the mandible arising from an odon- togenic cyst. Materials and Methods: An 80-year-old male was referred to Trieste University Maggiore Hospital (Trieste, Italy), with acute pain in the left retromolar area. An initial examination revealed extra oral swelling without paresthesia of the IAN. Following an intraoral examination, the oral mucosa was edematous, percussion pain was experienced on the lower left second molar. Panoramic radiography revealed a re- tained lower left wisdom tooth and an irregular radiolucent area between the lower left second molar and the mandibular angle with clear margins. Computed tomography re- vealed diffuse bone resorption and an extensive loss of cortical bone on the lingual side. Results: A biopsy was performed during the surgery to remove the second lower left molar and the wisdom tooth, the pathological diagnosis was of squamous cell carcinoma arising from the epithelial lining of the odontogenic cyst. MRI with contrast agent was also performed. Shortly after the patient has been proposed a complete resective surgery of the mass including the infiltrated areas and then a reconstructive part to restore the function and aesthetic. Conclusion: The follow-up of a large inflammatory cyst is essential for early diagnosis of malignant neoplasm. This approach allows lower invasive treatments and major survival of these patients.