Lymph nodes and malignant tumors

The planning of locoregional tumor therapy (radical surgical resection, curative radiotherapy) is based on the knowledge of locoregional tumor spread, in particular lymph node metastasis. In general, lymphatic spread follows anatomic rules, skipping of nodes is observed maximally in 3%. According to tumor site, uni- or multidirectional lymph drainage is found. In some tumors (carcinoma of penis, malignant melanoma, breast carcinoma) the concept of detection and examination of sentinel node increasingly is of importance. Lymph node metastasis is to be distinguished from the finding of isolated tumor cells in the sinus of lymph nodes (tumor cell emboli). A definite diagnosis of lymph node metastasis requires a careful histopathologic examination. The incidence of regional lymph node metastasis predominantly depends on tumor type, histological grade of differentiation, lymphatic invasion and depth of invasion/tumor size/tumor volume. A careful histopathologic examination of tumor resection specimens in regard of lymph node metastasis is important for indication to additional postoperative treatment, estimation of prognosis and analysis of treatment results. Adequate quality assurance is necessary.