Osteochondroma of the mandibular condyle: a case report and review of the literature.

Osteochondroma is rarely found in the oral and maxillofacial regions. A rare case of osteochondroma affecting the mandibular condyle of a 46-year-old Japanese woman is reported. Clinical examination revealed facial asymmetry, malocclusion, and a palpable hard mass in the right temporomandibular joint (TMJ). Radiologically, the lesion was visualized as a radiopaque mass in the same region, but no destructive features were evident. Three-dimensional computed tomography was employed for estimating the stereographic extension of the lesion, which seemed to develop from the anterior portion of the condylar neck, and extend to the condylar head. The patient underwent tumor excision and condyloplasty under a clinical diagnosis of benign TMJ tumor. The histopathological diagnosis was osteochondroma of the mandibular condyle, and the lesion consisted of proliferative bony and hyalinized cartilage-like tissues. Moreover, a cartilage cap, a characteristic feature of osteochondroma, was also observed. Thirty-eight cases of osteochondroma of the mandibular condyle described in the English literature, including the present case, were reviewed. The mean patient age was 39.7 years with a peak in the fourth decade, which was older than patients with tumors in the axial skeleton. There was no sexual predominance for tumors in either the mandibular condyle or axial skeleton. The histopathogenesis of this tumor developing in the mandibular condyle was also discussed.