Lymphatic metastasis

Abstract

Lymphatic metastasis is an important mechanism in the spread of human cancer. During its course, tumor cells first penetrate the basement of membrane of the epithelium, in which they arise, and then the underlying connective tissue, carried partly by hydrostatic pressure. They enter the lymphatic partly by active movement, pass up the lymphatic trunk; they then settle and proliferate in the subcapsular sinus, penetrate its endothelium and proliferate and destroy the node. There are varied forms of immune response in the node and in human nodes often a complex fibrous and vascular response. The degree of lymphocytic response may be important for prognosis. The nodal reaction may be stimulated by release of antigens from the tumor. One of the most studied animal models of lymphatic metastasis is that which occurs in the politeal node after injection of tumor into the footpad. This model has been used to show that tumor cells enter lymphatics through gaps in endothelium, probably between endothelial cells, and that lymph nodes can destroy small numbers of tumor cells. Local immunotherapy and chemotherapy can sterilize a lymph node of tumor cells; the modes of treatment used have included intralymphatic injection and encapsulation of chemotherapeutic agents in liposomes. Prior radiotherapy may accelerate metastasis possibly by making tumor cells shed into lymphatic vessels. Lymph nodes are rather poor barriers to tumor cells. The prognostic significance of lymph node metastasis varies within tumor type; if hematogenous metastasis is early, then the presence of lymph node metastasis is of lesser prognostic significance. Lymph nodes can probably destroy only small numbers of tumor cells. Tumor cell heterogeneity is of importance in many aspects of metastasis; while clonal variation may be of importance in determining lymph node metastasis, it is not yet clear how important this is, nor whether specific clones metastasize specifically to lymph nodes. Lymphography is well established in diagnosis of lymphatic metastasis. A recent interesting development has been to inject antibodies labeled with a radioactive label, and image the label in lymph nodes with a gamma-camera. If anti-tumor antibodies are used in this way it may be possible to detect lymph node metastasis. Within the expanding field of tumor metastasis, lymphatic metastasis needs much more attention, particularly in relation to the diagnosis and treatment of the lymphatic spread of human cancer.

Lipoxygenase mediates invasion of intrametastatic lymphatic vessels and propagates lymph node metastasis of human mammary carcinoma xenografts in mouse

“…One variant implies single tumor cell penetration between or even through endothelial cells, possibly also involving tumor cell epithelial-mesenchymal transition (21,46,47). In this investigation, we provide evidence for another pathway for mammary carcinomas similar to that previously described (45), which involves bulk invasion of metastatic tumor cells through large discontinuities of the lymphatic vessel wall. This pathway matches with recent experimental results obtained by in vivo microscopy in which xenografted mammary carcinoma cells spontaneously form mobile cohesive groups that preferentially invade into lymphatic vessels (24).…”

“…Several pathways of tumor invasion into lymphatic vessels have been observed for different experimental and human tumors (45). One variant implies single tumor cell penetration between or even through endothelial cells, possibly also involving tumor cell epithelial-mesenchymal transition (21,46,47).…”

Possible pathological basis for false diagnoses of lymph nodes by USPIO‐enhanced MRI in rabbits

“…Macrophages are mainly distributed in the medullary cord and medulla lymphatic sinus, which surrounds the lymph node hilum (25,26). Therefore, the ring-like USPIO enhancement in the rabbit inflammatory lymph nodes represents the medullary distribution of USPIO-labeled macrophages, while the surrounding paracortex and cortex areas with few macrophages are visualized as a bright rim in MR images.…”

Significance of parotid metastases of squamous cell carcinoma of scalp

“…So imponieren eine Lymphozytenexpansion mit Verbreiterung der kortikalen Bereiche und eine Zunahme der Makrophagen in der Markzone. Tumorantigene werden vermehrt präsentiert und so B-Lymphozyten aktiviert (Carr, 1983). Neben der durch die T-Lymphozyten vermittelten Zytokinproduktion, kommt es so zur Antikörperproduktion, die aufgrund ihrer Unspezifität meist nicht effektiv ist.…”