The effect of intestinal lymph on blood pressure in rats was observed by the methods of lymph drainage and lymph infusion.

Secondary lymphangiectasia may be caused by granulomas or cancer causing lymphatic obstruction, or increased central venous pressure (CVP) causing abnormal lymph drainage.

Because the trachea and thyroid gland adjoin to the subglottic area, the tumor invades them along with the superior mediastinum and lung by the way of paratracheal lymph drainage.