Abstract
One hundred and two cases, diagnosed as squamous cell carcinoma of the mandibular gingiva, were clinicopathologically examined. According to the mode of mandibular invasion, all cases were histologically classified two groups : 1) expansive type (80%) and 2) invasive type (20%) . The expansive type carcinomas were found to have a well-defined smooth borderline, while the invasive type had a diffuse irregular margin with infiltrative growth pattern.
These two histopathological types of mandibular gingival carcinoma were compared. The histopathological types were closely associated with radiographical types of mandibular resorption, pressure and moth-eaten types. The cases of expansive type showed radiologically pressure type (70%) and moth-eaten type (30%), and all cases of invasive type showed moth-eaten type. Histologically, the bone resorption was occurred befor carcinoma invasion in the expansive type. On the other hand, in the invasive type the bone resorption was occurred after carcinoma invasion or synchronously. In the expansive type Howship's lacunae in the reformation phase were relatively marked, while a large number of Howship's lacunae in the resorption phase were observed in the invasive type. Especially, histological examination showed that the intra-mandibular canal inf iltrasion without bone resorption was revealed in cases of invasive type, only. The 5-year survival rate of total cases was 75% in the expansive type and 32% in the invasive type.
These results suggested that the histopathological types of mandibular carcinoma, expansive and invasive types, were useful classification for oral oncologists.
