A 28-year-old man was hospitalized more than 15 timesfrom 2005 to 2008 at the Department of Otolaryngology atour institutions because of chronic, recurrent osteomyelitisof the maxilla on the right side. His medical history began in1994 (when he was a healthy 16-year-old boy without anyallergies or medication intake). At that time, a simple dentalprocedure of excision of an epulis located between theupper molar teeth on the right side was performed. Theprocedure was complicated by opening of the maxillarysinus from the oral cavity, which was surgically closed atthat time. Since then, recurrent right-side sinusitis had de-veloped multiple times with several puncture proceduresand empiric antibiotic therapies. In 1995, a Caldwell-Lucprocedure was performed on the right side with bilateralinferior turbinate submucous resection. Histopathologic ex-amination showed a nonspecific chronic inflammation. Af-ter surgery, the patient felt worse and noted an ongoingsensation of pressure around the tooth, swelling of thecheek, purulent discharge from the nose, and recurrentfever. He was hospitalized at the Department of Otolaryn-gologyoftheMedicalUniversityofGdan´sk,Gdan´sk,Poland,from May to August 2001. He was admitted for facial edemaand subfebrile body temperature; the symptoms appeared afew weeks before hospitalization. Computed tomography(CT) scan showed mucous membrane edema in both max-illarysinusesandedemaoftherightcheekandlowereyelid.Bacteriologic investigations of the nose swabs were nega-tive (Table 1). The results of the other laboratory tests wereas follows: white blood cell count, 8,600 L; erythrocytesedimentation rate, 6 mm; and C-reactive protein level, 3.0mg/L. The patient was treated with intravenous empiricantibiotics (600 mg of clindamycin 3 times daily for 14 days,2.0 g of ciprofloxacin 2 times daily for 3 weeks, and 500 mgof metronidazole 3 times daily for 14 days); at the begin-ning, the symptoms ceased, but within the next 2 weeks,the symptoms returned. Bone scintigraphy showed a highmarker concentration in the right maxilla. Next, a CT scanshowed a hypodense, encapsulated lesion inside tissue ofthe thickened cheek and edema of the mucous membraneof the right maxillary sinus (in its lateral-upper recess).Blood tests for perinuclear antineutrophil cytoplasmic anti-bodies (p/ANCA) and cytoplasmic antineutrophil cytoplas-mic antibodies (c/ANCA) were negative. The patient under-went surgical treatment. On the basis of clinical andpathologic findings (inflammatory infiltration), the diagno-sis of zygomatic osteitis was established. The patient re-ceived 20 expositions of hyperbaric oxygen therapy (HBO)(with protocol of a 70-minute time of exposition, 100%oxygen concentration, and 2.5 atmospheric pressure) withgood local outcome. After that treatment, he was healthyfor 4 years with occasional fullness and tenderness in the