Bizarre parosteal osteochondromatous proliferation of the maxilla: a case report.

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion of bone, known as Nora's lesion. The lesion often behaves like a malignant tumor, clinically and microscopically. BPOP usually occurs in the small tubular bones of the hands and feet, and a lesion arising in the oral and maxillofacial region is extremely rare. In this report, we present a case of BPOP arising in the maxilla of an adult woman, in the absence of trauma. After the initial lesion was excised, the patient began orthodontic treatment. The lesion recurred twice, both times appearing in almost the same location. Finally, the lesion was excised via marginal resection of the maxilla. In this case, it is suspected that the orthodontic treatment may have affected the recurrence of BPOP, because there was no history of trauma.