Metachronous odontogenic keratocyst and non-ossifying fibroma of the mandible

Although non-ossifying fibromas (NOFs) occur relatively commonly in the metaphysis of long bones, NOFs in the jaw bones (mandible and maxilla) is quite rare. After conducting a thorough search of the literature, twenty-five total cases involving NOF in the jaw bones were found. The current report describes a case of NOF discovered in the left mandibular condyle of an 11-year-old-female with a previously treated odontogenic keratocyst (OKC) of the ipsilateral side of the mandible. The patient was treated with transcervical removal of the left condylar head lesion with extraoral vertical ramus osteotomy (EVRO) extracorporealization, plating and bone grafting. Microscopic examination of the specimen demonstrated a hypercellular mass composed of spindled cells arranged in a storiform pattern with scattered osteoclast-type giant cells. The dimensions of the gross specimen were 1.5 x 0.8 x 0.7-cm. This is the fifth case reported of condylar head NOF and the first reported case of metachronous OKC and NOF of the ipsilateral mandible. The purpose of this report is to present a unique case of NOF coincident with an ipsilateral OKC of the mandible and to review the radiographic and clinical features of the NOF in the jaws.