BACKGROUND Both mandibular condylar hyperplasia and condylar osteochondroma can lead to maxillofacial skeletal asymmetry and malocclusion, although they exhibit different biological behavior. This study attempted to compare the histological features of mandibular condylar hyperplasia and condylar osteochondroma using hematoxylin-and-eosin (H&E) staining, and immunohistochemistry staining of PCNA and EXT1 with quantitative analysis method. RESULTS The H&E staining showed that condylar hyperplasia and condylar osteochondroma could be divided into four histological types and exhibited features of different endochondral ossification stages. There was evidence of a thicker cartilage cap in condylar osteochondroma as compared condylar hyperplasia (P = 0.018). The percentage of bone formation in condylar osteochondroma was larger than was found in condylar hyperplasia (P = 0.04). Immunohistochemical staining showed that PCNA was mainly located in the undifferentiated mesenchymal layer and the hypertrophic cartilage layer, and there were more PCNA positive cells in the condylar osteochondroma (P = 0.007). EXT1 was mainly expressed in the cartilage layer, and there was also a higher positive rate of EXT1 in condylar osteochondroma (P = 0.0366). The thicker cartilage cap, higher bone formation rate and higher PCNA positive rate indicated a higher rate of proliferative activity in condylar osteochondroma. The more significant positive rate of EXT1 in condylar osteochondroma implied differential biological characteristic as compared to condylar hyperplasia. CONCLUSIONS These features might be useful in histopathologically distinguishing condylar hyperplasia and osteochondroma.

中文翻译：

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con突增生与con骨软骨瘤的组织病理学特征：一项比较研究。

背景技术下颌con突增生和dy突骨软骨瘤都可导致颌面部骨骼不对称和错牙合，尽管它们表现出不同的生物学行为。本研究试图通过苏木精和曙红（H＆E）染色以及PCNA和EXT1免疫组化染色的定量分析方法，比较下颌con突增生和dy突骨软骨瘤的组织学特征。结果H＆E染色显示con突增生和con突骨软骨瘤可分为四种组织学类型，并表现出不同的软骨内骨化阶段特征。有证据表明，与con突增生相比，con突骨软骨瘤的软骨帽较厚（P = 0.018）。con突骨软骨瘤中的骨形成百分比大于con突增生中的骨形成百分比（P = 0.04）。免疫组织化学染色显示，PCNA主要位于未分化的间充质层和肥大软骨层中，并且the突骨软骨瘤中的PCNA阳性细胞更多（P = 0.007）。EXT1主要在软骨层中表达，con突骨软骨瘤中EXT1的阳性率也更高（P = 0.0366）。较厚的软骨帽，较高的骨形成速率和较高的PCNA阳性率表明con突骨软骨瘤的增殖活性较高。与con突增生相比，con突骨软骨瘤中EXT1的阳性率更高，这意味着生物学特性有所差异。