Abstract
Assessment of the distribution of lymphatic capillaries in the connective tissue underlying tumors is very important when attempting to explain the mechanism by which cervical lymph node metastases arise from tongue cancer. The left lateral border of the hamster tongue was rubbed with a dental cleanser in the control group. In the experimental group, it was further treated with a 2.0% solution of 9, 10-dimethyl 1, 2 -benzanthracene acetone (DMBA) to induce an infiltrated tongue cancer. Frontal sections of the tongue from each group were stained with 5'-nucleotidase (5'-Nase) and the lymphatic capillaries were examined under a light microscope.
In the control group, the lymphatic capillaries were present in all connective tissue papillae. These lymphatic capillaries arose from the lymphatic capillary network in the lamina propria mucosae. In the experimental group, the lymphatic capillaries were also present in the connective tissue underlying the tumor so that the connective tissue structure resembled papillae. Lymphatic capillaries underlying the tumor were significantly thicker in diameter than those in the control group. The 5'-Nase activity was lower in the experimental group than in the control group.
It is conceivable that an increase in diameter is necessary so that the lymphatic capillaries can absorb a large quantity of tissue fluid. Lymphatic capillaries underlying the tumor always maintained a plexus. This result suggested that the lymphatic capillary network in the connective tissue underlying the tumor was repeatedly built and destroyed as the tumor invaded the muscle layer. An inverse relationship between 5'-Nase activity and the diameter of the lymphatic capillaries was also suggested by the results of this study.
Therefore, 5'-Nase staining was very useful for observing the lymphatic capillaries in the connective tissue underlying infiltrated squamous cell carcinoma of the tongue.
