Troisier sign and Virchow node: the anatomy and pathology of pulmonary adenocarcinoma metastasis to a supraclavicular lymph node.

Metastatic spread of cancer via the thoracic duct may lead to an enlargement of the left supraclavicular node, known as the Virchow node (VN), leading to an appreciable mass that can be recognized clinically - a Troisier sign. The VN is of profound clinical importance; however, there have been few studies of its regional anatomical relationships. Our report presents a case of a Troisier sign/VN discovered during cadaveric dissection in an individual whose cause of death was, reportedly, chronic obstructive pulmonary disease. The VN was found to arise from an antecedent pulmonary adenocarcinoma. Our report includes a regional study of the anatomy as well as relevant gross pathology and histopathology. Our anatomical findings suggest that the VN may contribute to vascular thoracic outlet syndrome as well as the brachial plexopathy of neurogenic thoracic outlet syndrome. Further, the VN has the potential to cause compression of the phrenic nerve, contributing to unilateral phrenic neuropathy and subsequent dyspnea. Recognition of the Troisier sign/VN is of great clinical importance. Similarly, an appreciation of the anatomy surrounding the VN, and the potential for the enlarged node to encroach on neurovascular structures, is also important in the study of a patient. The presence of a Troisier sign/VN should be assessed when thoracic outlet syndrome and phrenic neuropathy are suspected. Conversely, when a VN is identified, the possibility of concomitant or subsequent thoracic outlet syndrome and phrenic neuropathy should be considered.