Anatomy of right recurrent nerve node: why does early metastasis of esophageal cancer occur in it?

Early, distant and/or skip metastasis of squamous-cell thoracic esophageal cancer frequently occurs in the right recurrent nerve node (recR). However, the specific lymphatic route without a nodal relay, such as the submucosal ascending route, was not known for the recR afferent. Using 20 donated cadavers, macroscopic, and histological observations were performed on the recR and its surrounding lymphatics, especially afferent routes from the esophagus to the recR. Most afferent vessels of the recR originated from the right paratracheal node. However, the recR often (12/20) received a major submucosal lymphatic drainage route ascending along the thoracic esophagus. The submucosal vessel came out of the esophagus and ran in a longitudinal connective tissue mass along the right tracheo-esophageal groove. A direct drainage route was often (13/20) seen from the recR to the venous system. Moreover, because of the specific histology, collaterals seemed to be present around the recR. In the regional nodes of the intrathoracic esophagus, the recR histology was characterized by the high proportion of lymphocyte accumulating areas or the cortex. From the midthoracic level, metastatic cancer cells seemed to reach the recR via esophageal submucosal vessels in the early stage. Large lymphocyte accumulating areas of the recR suggested higher filtration capacity than other distal nodes. However, the collateral of the recR and its direct drainage to the venous system suggested that the recR involvement often corresponds to a systemic disease.