A 61-year-old male patient was referred to our hospital because of gradual painful enlargement of the left parotid, buccal and parapharyngeal region, of three days duration. The patient complained of difficulty and pain while attempting to open his mouth or swallow. Low-grade fever of up to 37.6oC was reported. Treatment with oral antibiotics was introduced 2 days prior to presentation at the hospital, without signs of response to therapy.

The patient had a 3-year history of colorectal cancer with liver, bone and soft tissue metastases. Seven days prior to presentation, a course of radiation therapy to the cervical spine, administered for a paravertebral soft tissue metastasis, was completed. The patient was also receiving second line chemotherapy with cetuximab (an EGFR inhibitor) plus irinotecan, the last cycle being administered 20 days earlier. His treatment regimen also included chronic zoledronic acid monthly infusions, and dexamethasone, at a current total daily dose of 6 mg, as well as opiod analgesics.

Five months earlier, the patient had developed a pulp infection of the lower left second molar tooth, which required tooth extraction and antibiotic treatment. Although symptoms of local inflammation had completely resolved, the patient reported a persistent foreign body sensation in that area ever since. The rest of the patient's medical history was unremarkable, except for arterial hypertension.

Physical examination revealed a tender, crepitant, erythematous mass of the left parotid, buccal, infratemporal and parapharyngeal region (Figure 1). Trismus and dysphagia were also observed. Intraorally, a portion of exposed bone was identified at the molar area of the left mandible. The exposed bone had a yellow-white, smooth surface, and it was hard and painless. It was surrounded by erythematous, ulcerated and tender oral mucosa. The rest of the oral examination was normal. Despite the striking local findings, the general condition of the patient was not severely compromised, and body temperature was normal.

Baseline routine laboratory investigations showed a normal white blood cell count of 8,860/mm3 with predominance of neutrophils (95.4%), a 35-fold elevated C-reactive protein value of 17.7 mg/dl, along with an erythrocyte sedimentation rate of 83 mm/h, all consistent with acute inflammation. Hypoalbuminemia (2 g/dl) was also noted, as well as elevated blood urea nitrogen (47 mg/dl).
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Figure 1 : Site of osteonecrosis in the lingual side of the mandible (area of second molar)