Abstract
Fourteen skin tumors derived from oral squamous cell carcinomas were studied clinicopathologically. All tumors underwent curative resection in our department and showed pathological evidence of skin invasion.
Skin invasion was typically situated in the regions of the face and neck adjoining the primary site. In all cases diffuse types of invasion (grade III and IV) predominated according to Willen's mode of invasion. However, there were no differences between recurrent and non-recurrent skin tumors in the mode of invasion or the WHO histological grade of the primary tumor. Histologically recurrent skin tumors were characterized by higher levels of invasion into capillaries, nerves, periosteum and bone, compared with non-recurrent skin tumors.
Cancerous nests of recurrent skin tumors were small and cord-like in shape. All cases with satellitosis were recurrent.
Evaluation of the histological effects of preoperative irradiation on the skin tumors by the Shimozato-Oboshi classification indicated low effectiveness in the majority of cases. There were no differences in histological effects between recurrent and non-recurrent skin tumors.
Lymph node metastases were found in 11 cases, the majority of which were recurrent.
Distant metastases were found in only 2 cases, both of which were reccurrent.
Based on these results, a safe surgical margin for the resection of skin tumors derived from oral squamous cell carcinomas was investigated.
