Ossifying fibroma in the mandibular angle mimicking metastatic clear cell renal cell carcinoma: A case report

Rationale:Ossifying fibroma is benign fibro-osseous neoplasm. The authors report a case of ossifying fibroma in the mandibular angle suspected as metastasis of clear cell renal cell carcinoma.Patient concerns:A 74-year-old man presented to the primary hospital complaining of frequent urination. A tumor in the left kidney was detected via an abdominal computed tomography scan. The patient then visited the Department of Urology at our hospital.Diagnoses:According to whole-body imaging examinations, the patient was suspected of having renal cancer with mandibular metastasis. Also, a cystic lesion of the maxilla was revealed.Interventions:Left nephrectomy was performed by urologists, and the patient was diagnosed with clear cell renal cell carcinoma of the left kidney. Approximately 1 month later, resection with a safety margin of the mandibular lesion and removal of the maxillary lesion were performed by oral and maxillofacial surgeons.Outcomes:The patient was diagnosed with ossifying fibroma of the mandible and an odontogenic keratocyst of the maxilla via a histopathological examination. Eighteen months have passed since the operation without clinical and imaging findings associated with recurrence.Lessons:Ossifying fibroma in the mandibular angle of elderly patients is extremely rare. Surgeons should consider the possibility of metastasis when osteolytic lesions of the jaw are found in patients with cancer.