Hisashi Ozaki, Erika Miyamoto, Hiroki Mori, Yosuke Kobayashi, Yoshihiko Yokoe, Yuichiro Imai
Condylar osteochondroma is a rare condition that is more common among middle-aged women. Differential diagnoses for condylar osteochondroma include benign or malignant tumors and hyperplastic lesions. In particular, the differentiation between condylar osteochondroma and condylar hyperplasia is difficult due to similar clinical and imaging findings. Here, we describe a rare case of condylar osteochondroma in an older adult woman and discuss the differentiation from condylar hyperplasia, along with the clinical course. The patient was a 63-year-old woman with main complaints of facial asymmetry and malocclusion. Based on various imaging findings, the clinical diagnosis was a benign bone tumor of the left mandibular condyle. Low condylectomy was performed, improving facial asymmetry and malocclusion. Hematoxylin and eosin staining of the resected specimen demonstrated that the basic structure of the mandibular condyle was generally preserved. The surface of the tumor contained fibrous, cartilaginous, and cancellous bone layers. Chondrocytes were small, with no apparent cartilage islands. Based on these findings, a definitive diagnosis of condylar osteochondroma was made. Currently, histological examination is considered the most useful method for differentiating between condylar osteochondroma and condylar hyperplasia.