Cellulitis Extending from Submandibular to Temporal Region Originating from Bisphosphonate-related Osteonecrosis of the Mandible

We report a case of bisphosphonate-related osteonecrosis of the jaw (BRONJ) that caused cellulitis extending from the submandibular to temporal region. An 81 year-old man was referred to our department because of trismus and painful swelling of the left mandible, for which extraction of the wisdom tooth had been performed 3 months prior. He suffered from bone metastasis of prostate cancer, and was being administered anticancer drugs and zoledronate. A physical examination revealed an exposed jaw bone, and our clinical diagnosis was BRONJ with secondary infection. Five days after his first visit, the patient suffered from rapidly increased painful swelling extending from the submandibular to temporal region. Following admission, incision of the submandibular abscess was performed and acute phase inflammation was tentatively relieved. However, painful swelling in the temporal region recurred and an incision of the temporal skin for drainage was performed, which caused persistent purulent discharge. We performed a computed tomography examination, which excluded temporal bone necrosis. Thereafter, irrigation of the abscess cavity and systemic antibiotic chemotherapy were maintained. Although the exposed jaw bone persisted, there was no further pus discharge from the incision wound and the patient was discharged 45 days after admission.