A rare case of combined bilateral hydrothorax and hydromediastinum was encountered during Total Parenteral Nutrition (TPN) via incannulation of the left internal jugular vein in a patient with advanced cancer of the portio. The possible anatomical and technical causes of this very serious complication were investigated in order to assess the importance of specific manual technique and to supply appropriate instrumental back-up that could prevent the recurrence of this sometimes fatal complication of TPN.