A Case Report of Primary Intraosseous Carcinoma of the Mandible Initially Diagnosed as Mandibular Osteomyelitis

Primary intraosseous carcinoma (PIOC) is a rare malignant tumor of the jaw, often diagnosed as odontogenic cysts or osteomyelitis. We report a case of a 53-year-old woman who was initially diagnosed with mandibular osteomyelitis resulting from pericoronitis of the left lower third molar. The patient underwent tooth extraction under general anesthesia, and the granulation tissue from the extraction socket was sent for histopathological evaluation, revealing moderately differentiated squamous cell carcinoma. Postoperative imaging revealed significant bone resorption, invasion of the mandibular canal, and proximity to a left submandibular lymph node. Based on these findings, the patient was diagnosed with PIOC and subsequently underwent left-sided neck dissection, hemi-mandibulectomy, and reconstructive surgery. Histopathological examination confirmed the diagnosis of PIOC, with no evidence of metastatic lymph nodes. The patient has remained disease-free for seven years and four months postoperatively. PIOC is believed to originate from odontogenic cysts and is often detected at advanced stages due to its intraosseous location. Diagnosis is based on the absence of continuity with the oral mucosa, absence of metastatic oral tumor, and presence of squamous cell carcinoma. Early diagnosis and treatment are crucial for improving patient prognosis and quality of life. This case underscores the importance of considering malignancy in cases of destructive bone resorption and highlights the importance of timely biopsy in preventing delayed treatment.