Histopathologic comparison of condylar hyperplasia and condylar osteochondroma by using different staining methods

Objective The objectives of this study were to investigate the application and differential diagnostic value of safranin O staining, safranin-fast green staining, and Runt-related transcription factor 2 (Runx2) immunohistochemistry with regard to condylar hyperplasia and condylar osteochondroma. Study Design Histopathologic presence was evaluated by using hematoxylin and eosin staining, safranin O staining, safranin-fast green staining, and immunohistochemistry of Runx2 in postoperative specimens of normal condyle (control), condylar hyperplasia, and condylar osteochondroma. Results Safranin O staining clearly highlighted the tissue structure of the condylar cartilage, especially the hypertrophic layer. The safranin-fast green method showed a contrast in staining between cartilage and subchondral cancellous bone in the condyle specimens. Both methods were better than hematoxylin and eosin staining for morphologically distinguishing condylar hyperplasia and condylar osteochondroma. The expression of Runx2 in condylar hyperplasia was significantly greater than that in condylar osteochondroma. Conclusions This study indicated that safranin O staining and safranin-fast green staining are effective staining methods to differentiate between condylar hyperplasia and condylar osteochondroma. Immunohistochemistry findings suggested that Runx2 is valuable in the differential diagnosis of these two diseases.