The Organ Status of Lymph Nodes in Cancer Metastasis

The orthodox teaching has long been that lymph transports cancer cells to ‘lymph nodes’, while blood transports them to extra-nodal structures called ‘organs’. This dual classification dates back to over a century ago when extra nodal tissues were called ‘conglomerate glands’, whereas lymph nodes were segregated from the rest and called ‘conglobate glands’. Today, this archaic division is no longer valid. Correctly defined, lymph nodes are organs in their own right. Definition aside, since lymph nodes are nourished through the aorta like the other structures hitherto called organs, it is erroneous to assume that blood-borne cancer cells invade these other structures and spare the lymph nodes. For the uniformities in the mechanism of metastasis to crystallize completely, the organ status of lymph nodes requires recognition.