Primary Intraosseous Squamous Cell Carcinoma of the Anterior Mandible Arising in an Odontogenic Cyst in 34-Year-Old Male

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare and aggressive malignancy arising exclusively within the jaws, without any initial connection with the oral mucosa. The etiology and the epidemiology are unclear due to the rarity of the disease, and there is no current universally accepted staging or treatment protocol. Clinically, the posterior mandible is the most affected site, and common symptoms are swelling and pain. The diagnosis is often difficult either because it requires stringent criteria to be satisfied or because of the absence of a pathognomonic histological pattern. Aggressive surgery is the first-choice treatment, often followed by radiotherapy. The lymph nodal status seems to be the most important factor influencing the prognosis, which is usually poor, with a 5-year survival rate ranging from 30% to 40%. In the present article, we report an unusual case of cystogenic PIOSCC interesting the anterior mandible of a young 34-year-old male, which came to our attention after complaint about recurrent infective episodes affecting a dentigerous cyst (impacted lower canine) discovered ten years before. The age, site, and extension are uncommon. Extensive surgical treatment with fibula free flap reconstruction, adjuvant therapy, and salvage surgery was carried out. The patient was disease-free at a 31-month follow-up.