Oral cutaneous sinus tract, vertical root fracture, and bisphosphonate-related osteonecrosis: a case report.

INTRODUCTION: Oral cutaneous sinus tracts (OCSTs) of dental origin are often initially misdiagnosed and inappropriately treated. Accurate diagnosis is especially important in cases of bisphosphonate (BP) therapy because extraction may lead to a risk of osteonecrosis. A case report of misdiagnosis related to a tooth with a vertical root fracture in an oncologic patient treated with BPs is reported here. METHODS: In 2011, a 75-year-old woman was examined at the oral medicine clinic because of pain and swelling of the left submandibular area. The patient's medical history included oral and intravenous BP therapy because she was diagnosed with metastatic breast cancer and left maxillary stage 1 antiresorptive agent-induced osteonecrosis of the jaw. The lower left odontogenic region showed no signs or symptoms, and no apical pathosis was observed on imaging. Although antibiotics were applied, clinical symptoms worsened and an OCST appeared. Intravenous antibiotic treatment was pursued. Biopsy and direct smear from fistula were not conclusive. A diagnosis of a nonexposed variant of stage 3 antiresorptive agent-induced osteonecrosis of the jaw was established. RESULTS: Symptoms resolved after 2 weeks of antibiotic treatment and reappeared a month later. Endodontic examination revealed that the origin of the OCST was tooth no. 18 caused by a vertical root fracture, and the tooth was extracted. The patient was scheduled for routine checkups because of the fact that osteonecrosis may occur in intravenous BP-treated patients. CONCLUSIONS: Early correct diagnosis can prevent unnecessary and ineffective antibiotic therapy and surgical intervention, which is not recommended in intravenous BP cases.