“Togetherness” of superior mesenteric vein and ileocolic artery: how 3D CT based understanding of unusual anatomy influences the approach to D3 lymph node dissection

Abstract Purpose: There are several uncertainties on proper borders for D3-lymph node dissection (D3LND) in right colon cancer. To standardize the approach to lymph node dissection, superior mesenteric artery (SMA) or superior mesenteric vein (SMV) were suggested as anatomical landmarks. There is still no consensus, if SMA or SMV should be accepted as a surgical trunk for D3LND. Moreover, spatial vascular anatomy of ileocolic vessels in relation to SMV and SMA should be considered to reach complete lymph node dissection. Methods: A 62-year-old female was presented with hepatic flexure colon cancer. On computed tomography (CT) scan it was shown that SMA was laterally to the left from SMV. SMV in its distal part was passing along ileocolic artery in caudal direction. To completely excise the lymph nodes, SMA was considered as a landmark to remove the mesocolic tissue between SMA and SMV. Results: As a result, 25 lymph nodes (LNs) along SMA and 8 lymph nodes along SMV were harvested. There were no metastatic lymph nodes found along SMA and SMV. Conclusion: This case demonstrates the importance of spatial anatomy consideration in defining landmarks to perform complete lymph node dissection. The so-called arteriovenous flap can be considered as an important area of mesocolic root, which may contain lymph nodes and should be excised to perform complete lymph node dissection.