Advanced Maxillary Squamous Cell Carcinoma With Extension to the Infratemporal Fossa Masquerading as Extensive Osteomyelitis: A Case Report.

Squamous cell carcinoma (SCC) of the maxilla is an uncommon malignancy that often presents at an advanced stage because of its nonspecific clinical features and proximity to adjacent anatomical structures. In rare instances, it may closely mimic chronic osteomyelitis, particularly when presenting as a non-healing extraction socket with exposed necrotic bone and extensive osteolytic destruction, leading to delayed diagnosis and treatment. We report a diagnostically challenging case of advanced maxillary SCC that initially masqueraded as extensive osteomyelitis. A 55-year-old female with a 20-year history of areca nut chewing presented with a three-month history of pain, swelling, and purulent discharge from the left posterior maxilla following extraction of a mobile maxillary molar four months earlier. Clinical examination revealed diffuse left midfacial swelling, mild restriction in mouth opening, and an ulcerative lesion involving the left maxillary tuberosity, posterior alveolar ridge, and hard palate, with exposed necrotic bone and palatal perforation. Contrast-enhanced computed tomography demonstrated extensive osteolytic destruction involving the hard palate, all walls of the left maxillary sinus, left pterygoid bone, left lateral wall of the nasal cavity, medial wall of the right maxillary sinus, and extension into the left infratemporal fossa, with imaging findings suggestive of extensive osteomyelitis. Incisional biopsy revealed well-differentiated SCC. Following multidisciplinary evaluation, the patient was treated with three cycles of induction chemotherapy using the docetaxel, cisplatin, and 5-fluorouracil (TPF) regimen, resulting in partial clinical improvement, and she continues under oncologic follow-up. Advanced maxillary SCC may closely mimic chronic osteomyelitis both clinically and radiologically, particularly when presenting as a non-healing extraction socket with exposed necrotic bone. Persistent osteomyelitis-like lesions, especially in patients with established risk factors such as areca nut use, should prompt early biopsy to exclude underlying malignancy. This case underscores the importance of maintaining a high index of suspicion; correlating clinical, radiological, and histopathological findings; and adopting a multidisciplinary approach to facilitate timely diagnosis and appropriate oncologic management.