Diagnosis
A computed tomographic scan of the head and neck was performed and revealed tumescence of the left masseter and the surrounding soft tissue, with focal areas of necrosis and areas containing gas (Figure 2). Gas extended ipsilaterally to the parotid space up to the infratemporal region, as well as to the submandibular and submental spaces, and reached dorsally the posterior triangle of the neck and the prevertebral space. Bulging of the left lateral wall of the oropharynx into the lumen was also noted.

The above findings guided to the diagnosis of a masticator space infection, extending to the adjacent orofacial, infratemporal and peripharyngeal spaces. Concomitant osteonecrosis of the jaw was also diagnosed by an experienced maxillofacial surgeon, on the basis of the typical clinical presentation.1 Due to the immunocompromised status of the patient, intravenous broad-spectrum combination antimicrobial therapy was administered, including piperacillin/tazobactam, ciprofloxacin and teicoplanin. Additionally, an intra-oral incision was performed and a drainage catheter was placed which yielded purulent material. Culture of the draining fluid revealed Escherichia coli and bacteria of the normal oral flora. The patient's clinical condition gradually improved, despite a falling white blood cell count, owing to the recent chemotherapy and radiation treatment. The drainage catheter was left in place for a total of six days and the patient was discharged from the hospital after eight days of stay, with oral antibiotics.

Teaching points
- Masticator space infections are more frequently odontogenic in origin, particularly from the area of the lower molar teeth. Trismus and dysphagia are the major clinical manifestations. These infections are commonly polymicrobial, due to anaerobic and aerobic pathogens of the normal oral flora, and have the potential to spread to adjacent deep neck spaces and thus cause severe complications.2,3
- In the case reported herein, no other source of the masticator space infection could be identified, than the molar area of the left mandible, which had characteristic features of osteonecrosis. Osteonecrosis of the jaw (ONJ) is now a well-recognized complication of chronic bisphosphonate therapy, particularly with zoledronic acid, which is usually administered in patients with malignant disease and skeletal involvement, such as patients with multiple myeloma or breast cancer.1,4
- Local infection has commonly been reported in conjunction with ONJ, but it is still unclear whether it represents a primary process, contributing to the development of osteonecrosis, or a secondary one.1,5,6 Nonetheless, any exposed bone is generally considered to represent infected bone. This case indicates that intra-oral infections associated with ONJ, may, in the commonly immunocompromised cancer patients, spread in adjacent orofacial or peripharyngeal spaces and thus be a source of potentially severe complications.

Acnowledgements
The case was prepared by Drs. I. Melakopoulos and D. Karageorgopoulos and was submitted for publication.

REFERENCES
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