Diagnostic studies on the regional lymph node metastasis of oral squamous cell carcinoma

To detect lymph nodes metastasis, clinical palpation, ultrasoundsonography (US) and 99mTc rhenium colloid lymphoscintigraphy (LSG) were carried out in forty-one cases of oral squamous cell carcinoma, and the results obtained from these examinations were compared to histopathological findings of the resected lymph nodes. All patients were classified according to TNM system, and only 56.9% of the lymph nodes diagnosed as metastasized by clinical palpation were confirmed histopathologically. As to the US findings, the involved lymph nodes showed heterogeneous or cyst-like hypoechogenisity. In LSG, the abnormal images detected by static imaging procedure were as follows: (1) absence, (2) enlargement, (3) blurred appearance, and (4) asymmetry of lymph node RI counts at the lymph node showing enlargement and absence with LSG were high and low, respectively. In relation to the histopathological findings, more than two thirds of the lymph nodes were occupied by tumor cells in the absent image, approximately half in the blurred image and less than one third with follicular hyperplasia in the enlarged image. The lymphatic flow, detected by dynamic imaging procedure, was disturbed and delayed on the tumor-bearing cervical side in most instances. The present results revealed that 85.7% of the involved lymph nodes were accurately estimated by using both US and LSG. So far as lymph node metastasis, US and LSG offered the different information so that a combination of US and LSG is thought to be useful for the detection of cervical lymph node metastasis in oral malignant tumors. (author) 65 refs