Figure 4: Schematic description of more-step development of cervical lymph node metastasis.
a) Tumor-induced lymphangiogenesis in the intra- and peritumoral and invasion of the tumor cells in the lymphatic system, b) Development of micrometastasis in the sinus area, c) Enlarged lymph node metastases and the related change of the angio-architecture of the affected lymph node by curved displacement of the vessels near the metastasis and genesis of an avascular zone in the metastatic area, d) Extracapsular spread with description of aberrant and subcapsular vessels as well as necrotic areas in the metastatic region.